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hubbabubba
July 22nd, 2010, 16:04
This evening, Ivan sent me an e-mail about a topic that, I think, may be of interest to some of you. With his permission, I'm reproducing it here;

Hello Guy, (note: yeah, that's my first name; Guy, pronounce it like the "gui" of guitar)

Earlier, I described the necessity of minute adjustments and being able to SEE the results of these adjustments changing contour lines. I found that I had to put an additional bulkhead at the front edge of the windscreen. I found that I had put the top edge of the fuselage about 0.03 foot too low at that point because I had done a single unbroken line from windshield's vertical frame to the next bulkhead forward.

....Concave.jpg shows the situation as I added the new bulkhead at the front edge of the windshield. As you can see, the outline then became CONCAVE which is not right. It should be convex or straight at all points. (I named this file wrong: The part is actually Y1.)


13385

....Convex.jpg shows the result after adjusting the top points of the next two or three bulkhead upward to re-create the convex shape. (I named this file wrong: The part is actually Y1.)


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....FrontalCheck.jpg shows a contour and streamline check of stringer Y2. (Y1 is on the centerline and doesn't show in this screenshot.) Note that absolutely NONE of the parts in this screenshot will appear in the model. These are the equivalent of my building templates and jigs.


13387

This check and adjustment was done in about a half hour. If this were a purely SCASM project, I don't believe I could have done this check and adjustment at all. Do you know of a way this can be done in SCASM? This "misalignment isn't usually visible in the simulator except via odd shadows in unusual places. I fix them because I KNOW they are there.

Take Care,

Ivan
July 22nd, 2010, 17:22
Hi Hubbabubba,

As you were pointing out, this isn't really a "Confrontation". It is more about the limitations of each method of building. I believe that a combination of both methods produces the best results.

AF99 has a pretty stupid assembly process. SCASM does allow for visual checks.

That third screenshot with all the front bulkheads displayed gives a pretty good impression of how I built the nose section of the P-40C. You might be wondering why some of the bulkheads are not symmetrical:

Sometimes this is because I am making a change that I am unsure of. The right side retains the pre-modification dimensions.

Sometimes the left side has a series of points that need to be as co-linear as possible. The missing points on the right side forces that segment to be a straight line which I can use as a reference to scoot a point fore or aft slightly for best alignment.

- Ivan.

hubbabubba
July 22nd, 2010, 20:18
Well, Ivan, I thought that "Visual vertices adjustments under AF99 compared to SCASM" was a bit dry for a title...:kilroy:

I had pretty much figured-out what you meant by "seeing" your model but, just to be sure, I assume that the line going left from the nose-spinner junction to the last bulkhead is the one we're talking about?

If so then, yes, AF99 is doing, for such job, a far better job than SCASM would, no contest.

AF99 is doing many things; it is a project-maker, a 3D CAD, a texture placer, a basic animator, and an assembler, all rolled into one program.

I simply think that it is an excellent 3D CAD.

The "Project Wizard" is a necessary evil (how many projects did I erased with that contraption in the beginnings!).

The texturing tool was created to make us cry and give up.:crybaby: Which I almost did until Signore Andrea Cini, creator of many AF99 add-ons, came to my help in pointing to me that American numeral notation is different than French method. Grazie mille Andrea! Once I had set my "Paramètres régionnaux" to take that into account, I was still crying... but, now going somewhere, I persevered!:jump:

The "one time" animator is doing his job, as long as you don't bother about gears popping in and out and silly prop discs. After all, Aircraft Animator wasn't created for nothing.

I could go on with the help files (not helping much), the keyboard functions that you have to learn by literally tripping on them (oh! so it can do that!), or the tutorial which show you how you will never do anything except a balsa model, but I won't.

As for the assembler, until our exchanges with Bretoal, I was living in a state of partial bliss born out of ignorance. I was, like you Ivan, slightly annoyed by AF99 parts and components quotas. I was also mystified by models that would not show properly, even when still under the parts/components limits.

But, after Bretoal's teachings, and the now famous "Ivan's conga", I started exploring models and was horrified, it is not too strong a word, by the incongruous mayhem coding procedure. I understand that in a "one size fits all" assembler, some unnecessary code is present. But it does not explain all of the "quirks and quacks" I found.

Enough ranting. So AF99 is good. That's why I'm using it pretty much in the same way you do. Here is proof of that;

13398

Of course, like you, it is mostly as jigs or templates that these parts were used. Look, for instance, at the two wood blocks on the hood. Their actual shape on the released models is quite different. But I try to solve any possible visual issues before stepping into SCASM. In the worst case scenario, I can always return to the "blueprints" and modify, or redo, a part/component (I never use structures).

As for concavities, the jeep is full of them! In your own example, I'm not even sure that your original concave parts would show in game. You would know it is there, but you would probably be the only person on this planet aware of this ugly blemish! LOL! In "limit cases" like this one, AF99 will probably do as if nothing happened, and gamers would be totally oblivious of that "imperfection".

Next time, I will tell you why I "abandonned" AF99.

Ivan
July 23rd, 2010, 03:54
Hi Hubbabubba,

I didn't know that your initial build for your Jeep was with AF99. I figured that your issue with relocating the floor of the Jeep was an issue because it was all SCASMed. From AF99, that relocation would be easy!

I DO notice something that needs a slight clarification though, or perhaps I already know: Your Jeep in AF99 has a rear wheel well. In your actual model, it appears not to have a wheel well because the cutout is a transparent texture. Is this because when the concave part is textured, the concavity (wheel opening) disappears?

Actually I have an interesting solution for my next large project which I anticipate will be a B-26 Marauder in honour of my neighbour Col. Wallace Boblitt: The aircraft will NOT be a single "Assembly", and will not be entirely "Buildable" using AF99. Its assemblies will require manual final assembly inside SCASM. That will allow the separate AF99 assemblies to be built and flipped around but each won't be the entire aircraft. They will have 2D templates to represent the parts that are missing so I can get an idea of the actual shape of the final product though.

Perhaps I should apply this technique to my incomplete Heinkel He 177? The B-25C won't get this treatment because it was a proof of concept that a decent twin engine bomber can get built within AF99 limitations.

BTW, you asked earlier (facetiously I believe) what my motto was. I told you, "As Real as I can Make It". THAT is why I keep adjusting the contours on my P-40C when I know there is a problem even though I am fairly certain the results are not really visible in the simulator. That is also the reason why my projects take forever.

- Ivan.

hubbabubba
July 23rd, 2010, 10:24
I DO notice something that needs a slight clarification though, or perhaps I already know: Your Jeep in AF99 has a rear wheel well. In your actual model, it appears not to have a wheel well because the cutout is a transparent texture. Is this because when the concave part is textured, the concavity (wheel opening) disappears?


I'm still a bit puzzled by that one:isadizzy:. "Your Jeep in AF99 has a rear wheel well."; no, it doesn't have a wheel well. The inside panel is the internal polygon of the back-sides. The external panel is a single trapezoid polygon which is textured with a transparent bitmap to create the "well". The wheels (right and left) are "glued" to their internal side steps (the slated front part and the horizontal part where the "toolboxes" are) and the "step-wheel" sub-assembly is "sandwiched" between outside and inside panels mentioned above. This is the trick here. Nice or what?!:jump:

The idea of sub-dividing a project in sub-assemblies was at the base of my exploration of SCASMing. Your conga was the other part of the equation. I simply pushed those principles to their logical conclusion.

In AF99, the architecture works a bit that way;

Is the POV over or under the the CoG?

If the answer is "under", then is the POV right or left of the CoG?

If the answer is "right", then is the POV front or aft of the CoG?

If the answer is "front" then show tail parts first, left wing parts second, cockpit parts third... etc...

Of course, this is only one branch of a very dense tree.

With my method, the architecture goes like that;

Glue part A to part B (a "part" can be a polygon, a component, or already glued "parts")

Glue part AB to C

Glue part ABC to D

Glue part Z to Y

Glue part ZY to X

Glue part ZYX to W

Glue part ABCD to ZYXW

Show part ABCDZYXW

This is, too, only a short sequence.

Try to imagine a jeep made with AF99 architecture. I've tried, but I can't. My imagination doesn't go that far :eek:.

I'm preparing a post where I will talk scale and precision of the two techniques. But feel free to ask other "impromptu" questions. Likewise for anyone interested.

Ivan
July 23rd, 2010, 14:55
I'm still a bit puzzled by that one:isadizzy:. "Your Jeep in AF99 has a rear wheel well."; no, it doesn't have a wheel well. The inside panel is the internal polygon of the back-sides. The external panel is a single trapezoid polygon which is textured with a transparent bitmap to create the "well".


Please see the attached image. I highlighted the outline of the wheel well that I can see in your AF99 model. Perhaps you didn't actually put this in the actual model?



In AF99, the architecture works a bit that way;

Is the POV over or under the the CoG?

If the answer is "under", then is the POV right or left of the CoG?


You just described one of the seriously "Goofy" things that AF99 does. The first viewing decision is Top-Bottom and should not be. Fore-Aft and Left-Right decisions should be made first. Also there is no possibility of a Fore-MID-Aft sequence when all the viewing decisions are made before any parts are displayed.

I will continue in another message.

- Ivan.

Ivan
July 23rd, 2010, 15:10
I was having trouble with dropped connections in my last message. Not sure why.

In showing your gluing sequence for ABCDZYXW, I believe you left out a very useful SCASM technique that I am sure you know:

With AF99, all pieces must be separated by "Glue" (viewing plane) that determines when to show part AB and when to show BA. Sometimes this determination doesn't need to be made, but there is no way to avoid this with AF99. This is one of its serious weaknesses.

Let's use the example of the common Radial engine. I attached a screenshot of a A6M2 Zero to illustrate:
The engine is made up of the following parts:
A. The face of the frong cylinder bank
B. The Interior of the cowl in front of the cylinders
C. The Reduction Gear Housing (Cone in the center of the engine)
D. The Exterior of the Cowl.

The viewing sequence is ALWAYS ABCD. There is NEVER a case in which a decision needs to be made. A never displays in front of B which never displays in front of C which never displays in front of D. SCASM can handle this. AF99 can't.

Now there ARE some screwed up ways to do this in AF99 such as putting the engine face in the Tail assembly, but you can't do this when there are a bunch of parts that need this treatment. I have seen folks put a Left side cockpit wall in the right wing assembly, Right cockpit wall in the left wing, etc. with each part as an insignia facing the opposite direction so that it doesn't show when you are on the side of the assembly, but this is seriously non-intuitive and a pain to track down.

- Ivan.

hubbabubba
July 23rd, 2010, 17:17
Please see the attached image. I highlighted the outline of the wheel well that I can see in your AF99 model. Perhaps you didn't actually put this in the actual model?

They say "an image is worth a thousand words"! How true! Yep, you're right, this part was only made to localize the "best" angle to cut between the rear and central "parts" (as in ABCD part). That obviously concave polygon never made it in the final model.


The viewing sequence is ALWAYS ABCD. There is NEVER a case in which a decision needs to be made. A never displays in front of B which never displays in front of C which never displays in front of D. SCASM can handle this. AF99 can't.

This is probably a case where my background in scenery macros was of help. We (scenery designers) often make entire buildings without using a single glue part. For example, the sequence of a simple house with a slanted roof would look something like that;

:simplehouse

call( :fronthouse )
call( :backhouse )
call( :leftsideHse )
call( :rightsideHse)
call( :leftroof )
call( :rightroof )
Return

Since the internal parts are never to be seen, there is no possible interference from the external parts. Better yet; suppose you want to be able to get in that house;

:simpleHseinout

call( :fronthouseins )
call( :backhouseins )
call( :leftsideHseins )
call( :rightsideHseins )
call( :leftroofins )
call( :rightroofins )
call( :floorins )

call( :fronthouse )
call( :backhouse )
call( :leftsideHse )
call( :rightsideHse)
call( :leftroof )
call( :rightroof )
Return

By placing the internal parts first in the showing order, the external parts cover them from the exterior. Once inside, you see only the interior parts. With transparent textures you could even have a look inside the house and, if a window is on the opposite side internally, a view of what is behind the house. Not a single glue part in that.

Which brings me to my next question; if your "one-way" ABCD sequence for A6M2 Zero can't be done in AF99, how did you do it? I know that AF99 can apply parts as "insignias", which are not glued. Was is your trick?

Ivan
July 23rd, 2010, 19:12
Hello Hubbabubba,

The "Trick" with Radial engines is something I worked out way back when I built my first Corsair. In this case, it is better illustrated with screenshots from the P-40C which uses the same technique with its radiator opening:

The Keel shot shows an entirely medium green nose up to the opening. One frame back from the opening is where everything comes together. The front face of the radiator is there. It is glued to the cowl not at the edge of the component but inside it. The cowl interior wall component is also glued at the same location sequenced AFTER the radiator. The radiator baffles are glued after the cowl interior, so up to this point, if we are forward of this frame, we see the baffles in the foreground followed by the cowl interior followed by the radiator face. The last component is the dark red cowl exterior that is also glued to the same frame so that when we are forward of that frame, we see it over everything else. If we are behind that frame, we see the green nose over everything else.

That pretty much illustrates the technique. There is one other issue: Because the baffles are glued forward, the last one glued will bleed through the opposite side. That is why there are insignia versions of each side (facing out) that are glued after the ones facing in.

The old P-40E was built with a much more complicated sequence and has a couple very slight bleeds when viewed from below. Knowing what I do now, it could have been built without those bleeds.

- Ivan.

hubbabubba
July 23rd, 2010, 21:58
PRECISION

AF99 works to the 1/100th of a unit. With the usual settings, the unit is one foot. Therefore, with AF99, you can, in theory, adjust to 1/100th of a foot.

But this is only in theory.

You see, when the assembler within AF99, a commercial flavor of SCASM btw, is doing its job, it has to adjust to SCASM scale: the meter. It also has to adapt to the internal scaling. Without going into details, the scaling command is "SetScalex", and it is set at "7". The mathematical relationship of this is that each units represent 1/512 of a meter, or 0.001953125 meter.

How much does a foot represent in meter? According to my converter program: 0.3048 meter.

How many SCASM units does AF99 take to represent a foot? 156

156 x 0.001953125 = 0.3046875

Pretty close... but...

To get an inch, you must round up: 1 foot divided by 12 = 0.0833333333333... , or 0.08 within AF99 limits.

How many SCASM units does AF99 take to represent an inch? 12

But wait a minute! 156 divided by 12 = 13! More than that; 12 x 12 = 144, not 156. In fact, 156 - 144 = 12! So AF99 foot is 13 inches long!

Now, AF99 can render 1/100 of a foot, or 0.01 foot.

How many SCASM units does AF99 take to represent 1/100 of a foot? 2

SCASM units are integers. You can't have 1.56 (156/100) for a unit, so it is rounded to 2.

Of course, with SCASM, you can go to one unit. The following animated gif shows an AF99 square foot (white), an AF99 square inch (blue), an AF99 smallest resolution of 2x2 and, finally, a "SCASM only" 1x1 square.

13470


The difference in precision may look trivial, but it is not. In lengths, it double the precision, in surfaces, it quadruple it and, in volumes, it multiply it by eight. If you remember, Ivan, the octagonal cross section of the MG canon holder was "lenticular" but, in AF99 blueprint, I can vouch that it was circular. At very small scale, AF99 starts to "lie" to you. Only SCASM precision could correct the visual imperfection at that level.

BTW, when I made the above GIF in AF99, all squares, although properly sequenced, were all glued together along impossible angles, creating a flickering effect. I just removed the gluing sequence and called all squares starting with the 1 foot square and finishing with the 1x1 square. What you see from the left side is exactly reproduced on the right side. AF99 can't do that.

My daughter was on the PC all evening and I had to wait at this hour to finish this post. Time for some rest now.

Ivan
July 24th, 2010, 19:51
Hello Hubbabubba,
I believe your description of the scale differences between AF99 and SCASM are somewhat misleading: There is no doubt that the unit in SCASM is more precise than that of AF99 (1/512 meter versus 1/100 foot).

For best results, one should be working to the native scale which is that of SCASM. I don't believe that working in AF99 units actually loses very much though. The resolution of AF99 is 0.01 foot or 0.12 inch (roughly 1/8 inch). The native scale in SCASM is 0.077 inch (roughly 1/13 inch).

Given an AF99 dimension, the conversion to SCASM internal units is never more than 2/512 meter or 1/6 inch off. As a result, sometimes a good curve might become less so, but the change won't be great.

Regarding Left-Right symmetry, I believe the calculations used by AF99 are generally stable. If you doubt this, pick any reasonable AF99 aircraft and view it in DPED. DPED works in meters but I haven't seen it show a difference between left and right sides of my models when I have been working on DP files. (....except for the BV 141....)

See the attached conversion chart. First column is AF99 units (0.01 foot). Second column is raw conversion to SCASM 1/512 meter. Third column is integer rounded. As you can see there are numbers that are skipped, but the error isn't cumulative.

A couple years ago, You and I were working on calculating the cockpit viewpoint for adjustment using SCASM. I refused to accept that a "guess" was the correct method to make this determination. In the final test, to prove that the SCASM unit was 1/512 Meter, I created a cube component about 1 inch on a side and put it centered on the estimated viewpoint. The result was that the viewpoint ended up within the cube because the cube was invisible. AF99 components (smooth) have all visible polygons facing outward which is why the cube was invisible. With a 1 inch cube, if the viewpoint was as much as a half inch off in any direction, the cube would be visible. That test showed that the cumulative dimensional error in AF99 is within that tolerance at least for my test.

I am not really sure what you mean about the barrel sleeve (? I believe a canon is a barrel?) being lenticular. If I remember right, you were doing your own conversions for dimensions for which I never knew the details. If you were using a AF99 structure to create the basic shape, I can see how that would be a problem because the cross sections are often not as good regular polygons as they should be.

Regarding "Inches": They are not an AF99 unit! I only use them to quote numbers that folks can intuitively understand. If I say 0.01 foot, folks will have to think a while. If I say 1/8 inch, most folks can see that. If they can't a 1/8 inch marking on a ruler is easier to find that a 1/100 foot marking. When working with drawings for a project, I convert all inch values to hundredths of a foot.

BTW, for folks who might want to test out the "Units" we are discussing, Use FDE to adjust a flight model's cockpit viewpoint in inches. (I believe this is record 301.) You will find that the values "snap" to discrete values. You can't just plug in any arbitrary value. AirED also snaps to values, but the problem is that their datatype is defined incorrectly to be an exact match to SCASM internal units. If your FDE doesn't show the right numbers, email me at Ivan1GFP@yahoo.com and I will send you my updated FDECTRL file which has the correct conversions.

- Ivan.

hubbabubba
July 25th, 2010, 01:29
Hello Hubbabubba,
(...)
Given an AF99 dimension, the conversion to SCASM internal units is never more than 2/512 meter or 1/6 inch off. As a result, sometimes a good curve might become less so, but the change won't be great.
(...)
I am not really sure what you mean about the barrel sleeve (? I believe a canon is a barrel?) being lenticular. If I remember right, you were doing your own conversions for dimensions for which I never knew the details. If you were using a AF99 structure to create the basic shape, I can see how that would be a problem because the cross sections are often not as good regular polygons as they should be.
(...)
- Ivan.

Hi Ivan:wavey:

I had to search into my "leftovers" of the MG jeep to find this;

13531

This is the part I'm talking about (pale blue), whatever its real name. To make a round octogon, I would make a temporary part and have it rotate by 45° and "save as". Then I would create the polygon using the "P" key. Up-down and right-left came OK, but the other vertices were shortened by AF99. The blueprint, as you can see, was not showing that; the octogon appears to be "round". This is when you told me that the model in game wan't round and, by gosh!, you were absolutely right!

The yellow octogon is my own representation of what was really happening. This is why I'm telling you that AF99 lies to us, especially close to the inferior limit of its precision.

The solution was to redo all the vertices under SCASM using a grid on a bitmap. This way, I could "elongate" the 45° angles that AF99 had "ignored" in rounding up.

The jeep is, compared to an aircraft, a very small object. The gun on top of such a jeep is even smaller. On an aircraft, a precision of ±2 SCASM units will probably do. With the gun, it wasn't enough.

I'm not trying to be misleading regarding the scale used by AF99, I'm simply thinking of the average designer that have to live with inches. When I was making the Taifun, I would translate all measurements, originally in metric system, to the imperial system! I'm not sure I would take the same path now btw...:icon_lol:

If someone is up to transferring all measurements in hundreth of a foot, the better.

Precision and scale was not the main reason I "defected" to SCASMing anyway. More on that later...

Ivan
July 26th, 2010, 03:10
Hello Hubbabubba,

I have a pretty fair idea of what a Browing .50 Caliber machine gun looks like, so I decided to try to build a component similar to what you are using for your barrel extension / barrel sleeve. The sizes may not be exactly the same, but should be within range. I didn't do anything particularly strange here. I just imported, rotated and resized the 8 point circle from the storehouse and used two different sizes as references to build a component. If you read the dimensions in the point editor, they are within reason for the precision of AF99.

It took a while to respond because I needed to actually try this out for myself. The end result is that I am getting more or less reasonable results in the simulator as I see it. I am not sure why your results are so strange. This thing is kind of small, so I had some trouble getting the alignment perfect in the simulator.

Easiest way to see if it looks right is to tilt your head slightly and see if the sides look "Square". They don't look exact but they don't look bad either.

BTW, I still think you should have used a Hexagon instead of an Octagon because of the three equally spaced rows of cooling holes.

- Ivan.

hubbabubba
July 27th, 2010, 04:43
Hi Ivan,

I just verified your two octagons and they are rather "round" indeed.

To make the barrel sleeve, I didn't used the "magnify" tool. For this octagon, I made a vertical line 0.24 AF99 units long and "saved as". Using the "rotation" and "bank" tool, I would turn the line by 45° increments and "save as". Three rotations later, I would have a four lines asterisk-like star. Using the "draw" and "P" tools, I would simply draw my octagon. Unfortunately, it is only after your acute eyes had discovered the deformation that I realized that the rotation tool was shortening the line during the rotation. For some reason, it cuts one AF99 unit at each end of the line, whatever the length of the vertical line. So my 0.24 units diameter in height (Up-Down) was only 0.22 units diameter in width (Right-Left). The 45° angle lines were also shortened.

But, using the "magnified" tool, I was not as lucky as you were with your 0.25 and 0.07 AF99 diameter units octagons. By chance or by design, these two octagons are almost looking the same once "saved as". Not so for my 0.24 units diameter octagon. Once "saved as", height and width are equal, but 45° angles are clearly too large. Here is a composite image of the three 0.24 units octagons;

13743

The narrowest octagon is the one I made with the "rotation" tool. The top vortex is at +0.12 and the bottom vortex at -0.12, but the rightmost vortex is at +0.11 and the leftmost vortex at -0.11. The 45° angled vertices are also too short when compared with the unsaved octagon made with the "magnify" tool (highlighted blue lines).
But, once "saved as", the octagon made with the "magnify" tool is also deformed. The 45° angled vertices are too long when, again, compared with the "ideal" octagon shown by AF99 before being saved.

I did the same exercise with a 0.25 and 0.07 octagons like yours and got almost exactly the same shape. Was it by chance or because you choose these sizes on purpose, only you can tell.

But the smaller it gets, the greater the chances AF99 will deform the "ideal" octagon. This animated GIF shows the muzzle bore hole as it would look before and after being saved; a tilted square or a lozenge, depending on your inclination (pun intended)! If you have a close look at my MG jeep, you will notice that it is fairly round. It is so simply because, under SCASM, I was able to put vertices in places AF99 couldn't.

13744

Ivan
July 27th, 2010, 05:51
Hello Hubbabubba,

I actually have no idea what the diameters are that you are using for your barrel sleeve. I just picked a couple arbitrary diameters that were in the range that I estimate the diameter is on the real gun. The smaller one is to make sure that I tried something smaller than you were likely to be using.

I now know the major diameter is .24 foot. What is the minor diameter so I can try the same test again?

- Ivan.

hubbabubba
July 27th, 2010, 18:38
The muzzle bore hole is 0.04 in diameter.

Ivan
July 28th, 2010, 07:45
Hello Hubbabubba,

I suspect 0.04 foot diameter probably won't work very well, but I will give it a try anyway when I get the chance. On something this small, doesn't it make better sense to just do it as a texture?

- Ivan.

hubbabubba
July 28th, 2010, 13:10
Hello Ivan,

If you persist working within AF99 limitations, I guess the answer is yes. :kilroy:

Some of the holes and "rivets" of the MG cradle are made the same way. The gun sight blade is only 0.01 foot large... but it split the right-left axis. With AF99, that blade would be as thin, but on one side or the other.

0.01 of a foot is very good, but 0.005 is even better:jump:!

Ivan
July 29th, 2010, 05:53
Hi Hubbabubba,

Attached are screenshots from AF99 with the point editor showing the coordinates for the 0.24 Octagon and my solution to the .50 caliber gun muzzle. Yes, the build process corrupted the dimensions a bit, but it still sorta works. Keep in mind that we are discussing a polygon that is only 0.02 in diameter. I had trouble finding it. As you can see the 0.24 Octagon turned out well enough. keep in mind that although rivets can be represented by polygons, that is computationally expensive. If you are going to texture the object anyway, why not put the rivets there? The only reason I can think of is that the smooting process corrupts the image a bit.

Yes, you are correct, SCASM does better, but I still don't think we are giving up much in precision using SCASM. As for quality of model, that is another story entirely. I agree that for a good model, AF99 output NEEDS some SCASM tweaking for things it cannot do and for removing some general stupids from the assembly process.

From a philosophical standpoint, we need to stop somewhere. If 0.01 foot is good and 0.005 foot is better then 0.001 foot must be even better??? AF5 had issues with 0.1 foot resolution which in my opinion made for very poor models, but 0.01 isn't that bad.

- Ivan.

hubbabubba
July 29th, 2010, 08:38
Hello Ivan,

Yeah, 0.01 isn't that bad, but the MG jeep would not exist in its present form if I hadn't used SCASM. I too would like to go to 0.001, but SCASM stops at 0.005 foot. On a philosophical standpoint, as you say, we are only limited by the tools we use; this is where we have to stop. Don't tell me that, if Abacus was to announce a "patch" bringing the precision of AF99 to 0.001 foot, you wouldn't download and install it?

The 0.24 octagon is too "fat" at the 45° angle vertices and the 0.02 octagon in radius is not round at all. Here is a picture showing the barrel from the sleeve to the muzzle. Compare "my" bore hole to yours. As you say, texturing would probably have "blurred" it. And you don't have to search for long to find it.

13884

On the left I'm showing the cradle and pintle. I could have textured the hole thing, but it was more expedient to use polygons and, besides that, the jeep already had enough textures. Incidentally, it is much more "computationally expensive" to apply texture than to create polygons. In its notes, Kukushkin , creator of AF5 BAO and AF99, had different SCASM commands run in a loop.

The command "Poly()", which I used for these polygons, was capable of running 460.29 instructions per second (it was probably an old 386...) while the command "ShadedTexPoly()" would only run 25.72 instructions in the same time. All things being equal, I could make more than 17 polygons for the "computational price" of one textured polygon.

But higher precision was only gravy...

Ivan
July 29th, 2010, 09:49
Hello Hubbabubba,

You are right: If there were ANY kind of a patch for AF99, I would probably install it.

You are the builder of the Jeep. If you believe SCASM was necessary for proper construction, who am I to argue? I will point out however that my original argument still holds: if you found that there needed to be minor tweaks for alignment to get a body panel to curve (Jeep? Curve?) correctly, you would have an extremely difficult time fixing things. I also believe that without a visual design package, I could not have done the fine tuning of contours for the recent P-40C.

With few exceptions, I prefer to texture pretty much everything in a model because the reflections and shadows look strange without textures. Besides, How much of the speed differences are due to texturing and how much to shading?

I actually had no luck with an octagon for the muzzle, so I used a small hexagon. I agree with you that even that hexagon doesn't look quite right. Regarding fuzzing due to textuers, I noticed that you have that issue with the rear wheel wells and the effect is much more visible than for the muzzle on a machine gun.

Your comment about the 45 degree vertices of the 0.24 polygon being too fat is interesting. You said *I* have good eyes. I am thinking yours must be much better: The dimension from the screenshot in AF99 is 0.17 feet for the 45 degree vertices. The actual number SHOULD be 0.169705627484 feet. It is too big by just under 0.0003 feet (0.0035 inch) or a bit less than the thickness of two sheets of paper.....

- Ivan.

hubbabubba
July 29th, 2010, 20:20
Your comment about the 45 degree vertices of the 0.24 polygon being too fat is interesting. You said *I* have good eyes. I am thinking yours must be much better: The dimension from the screenshot in AF99 is 0.17 feet for the 45 degree vertices. The actual number SHOULD be 0.169705627484 feet. It is too big by just under 0.0003 feet (0.0035 inch) or a bit less than the thickness of two sheets of paper.....

I was making an aesthetic appreciation here, not a Pythagorean calculation. To settle the matter, I took your "GunMuzzle.jpg", removed the 0.25 octagon to only keep the 0.24 and the little hexagon, made a double of the image and made the octagon yellow. After turning it clockwise by 90°, it was over imposed on the original one;

13929

If AF99 was making a perfect octagon, the yellow lines would cover the white lines, it is simply not the case here. The yellow octagon appears to be higher but narrower than the original white one. The 45° angles appear to be more or less at the same distance from the center but, given the wider original figure, they appear also wider. I repeated the experiment making my own 0.24 foot octagon along your method and got exactly the same distortion.

So, it is very possible - certain in fact - that AF99 blueprints are distorted OR that it lies about coordinates.

Which makes me rethink my comments about AF99 being a good CAD...:kilroy:

Ivan
July 30th, 2010, 08:09
Hello Hubbabubba,

I suspect there is more to the visual interface of AF99 than that. I have noticed that sometimes when adjusting a point using the point editor, the apparent movement of that point isn't consistent. I thought this was perhaps it uses metric measurements internally and it was a matter of snapping to points. (In other words, perhaps the SCASM scale conversion happens within AF99.

I have also noticed that when I run CFS, it screws up my display in AF99 and I need to restart AF99 to get a proper parts display. The change is in the aspect ratio; The left/right scale on the screen is doubled so that aircraft start looking long and skinny.

I always thought this was my computer because I also have a minor issue when using AF5Paint.

- Ivan.

hubbabubba
July 30th, 2010, 12:04
This is also why my octagon, that was short by two units right-left, looked OK to me. I had noticed that when the mouse cursor was hovering over the coordinates in the upper-right corner, the picture was stretched horizontally.

I used more or less the same visual trick on my octagon in game (yours is ¾ frontal) and it is not distorted, give or take a few pixels.

I guess we'll have to live with it. But it good to know.

Ivan
July 30th, 2010, 13:27
Hi Hubbabubba,

It wasn't my intent to get a 3/4 frontal screenshot. It was as close as I could get to a full frontal shot. It isn't all that far off considering that this almost cylinder is much longer than it is wide. Perhaps I should have just altered the AIR file to put the cockpit viewpoint right in front of the cylinder. I didn't do it because I have been putting these these test cases together in a few minutes and taking screen shots just before I leave on my commute to work.

Do you remember that way back when you were building your Taifun, I was commenting that textures for edges were not as good as polygons? Seems like our positions in this case are somewhat reversed when discussing the Machine Gun Muzzle. I suppose that with the .50 M2HB on a pintle mount, a proper muzzle is needed for "The Look", but for an airplane model, I generally don't even try to put a muzzle on any of the guns. Most of the time, I have even left off the gun barrels themselves.

- Ivan.

Ivan
August 25th, 2010, 12:57
Hello All,

Considering the discussion about representing the muzzle of a .50 caliber machine gun, consider how well such an object would show up in the simulator. The Spitfire's cannon are 20 mm or 0.787 inch and the Corsair uses .50 caliber guns. Muzzles of neither type of gun are typically visible in these views.

- Ivan.

hubbabubba
August 27th, 2010, 14:58
Hello All,

Considering the discussion about representing the muzzle of a .50 caliber machine gun, consider how well such an object would show up in the simulator. The Spitfire's cannon are 20 mm or 0.787 inch and the Corsair uses .50 caliber guns. Muzzles of neither type of gun are typically visible in these views.

- Ivan.
Hi Ivan,

As long as the muzzle is not seen directly in the external view, like the "Ma Deuce" jeep, it can be omitted. But what about a Bf109 with a motorkanone? For many Allied pilots, it was the last thing they could remember before being deported to the POW camps. The less fortunate would probably have said the same if they had survived.

Ivan
August 29th, 2010, 02:23
Is it the opening in the spinner which is only the blast tube or is it the muzzle of the cannon which can't be seen about 5 feet behind the spinner or is it the "Flush" (DPED term) that they are seeing? Or is it just a black dot inside a spiralling spinner which was typical of Luftwaffe aircraft of the period? Did they say the same about the FW 190A which didn't have Motorkanonen?

The FW 190A would have been a more common interceptor and the more dangerous one to bombers.

By my understanding, the 20 mm MG151/20 was a more common motor cannon than the MK108 even though the MK108 was more destructive. Also, from the characteristics of the guns, the MG151/20 should have put out a larger muzzle flush than the MK108. The MK108 was a very low velocity gun with very little propellant and a big A$$ shell which blew rather large holes in aircraft structure.

Any details to your assertion regarding bomber crew? If there were any statistics to be collected, the meticulous Luftwaffe would probably have done it.

BTW, a Me 109K is in my plans and yes, it MUST have an opening in the spinner for the cannon. Whether this is visible in combat is debatable though.... As designers, we all choose what we represent. In the case of the 109, I don't think I will bother with the aileron balance weights.

- Ivan.

hubbabubba
August 29th, 2010, 06:25
LOL!:icon_lol:

I have been using DPEd for ages and I never remarked that it was spelled "Flush"! I think it should read "Flash", but who am I to judge? LOL again!:icon_lol:

I was talking of the opening in the spinner, of course. What I was trying to explain is that they are circumstances where "detailing" is more important, like the motorkanone that the simmer will inevitably see from quite close quarter if he he goes front-back-front in external views. I remember reading an account by, I think, Gentile in which he was trying to shake-off a "Gustaf" by going vertical, the 109 on his tail. He could see the spinner cannon, probably in his rear mirror, coming closer and closer as his follower was climbing. I'm not convinced that Gentile, or whoever it was, debated the merits of the Mk 108 vs. MG 151/20 while its servant was trying to aim for a no-deflection shot.


Any details to your assertion regarding bomber crew?Which assertion? I make so many...


In the case of the 109, I don't think I will bother with the aileron balance weights.With the Taifun, I did bother. And I think I would still bother now that I'm SCASMing my projects.

Ivan
September 2nd, 2010, 06:37
You actually wrote "Pilots". I interpreted this to be "Bomber Crew" because for the most part, fighter pilots who get shot down never see their attacker. A dogfight isn't quite as common.

The typical Luftwaffe fighter of the time had a black spiral on the spinner or al all black spinner or a black and white spinner. I am guessing that in combat, most of the time the muzzle could not be seen. Gentile and the typical fighter pilot had excellent eyesight, but I am guessing that sometimes it was just imagination.

Imagine what would have happened had Gentile fought a G-10 Gustav or a K-4 Konig? The result may not have been the same against a superior fighter.

- Ivan.

hubbabubba
September 3rd, 2010, 18:02
(...)
He reverses his turn, trying to fall in behind us. My wingman is vulnerable now. I tell Skara, "Break off!" and be peels away. The German goes after him, and I go after the German, closing on his tail before he can close on my wingman. He sees me coming and dives away with me after him, then makes a climbing left turn. I go screaming by, pull up, and he's reversing his turn--man, be can fly!--and be comes crawling right up behind me, close enough that I can see him distinctly. He's bringing his nose up for a shot, and I haul back on the stick and climb even harder. I keep going up, because I'm out of alternatives.

This is what I see all these years later. If I were the sort to be troubled with nightmares, this is what would shock me awake. I am in this steep climb, pulling the stick into my navel, making it steeper, steeper . . . and I am looking back down, over my shoulder, at this classic gray Me 109 with black crosses that is pulling up, too, steeper, steeper, the pilot trying to get his nose up just a little bit more and bring me into his sights.

There is nothing distinctive about the aircraft, no fancy markings, nothing to identify it as the plane of an ace, as one of the "dreaded yellow-noses" like you see in the movies. Some of them did that, I know, but I never saw one. And in any event, all of their aces weren't flamboyant types who splashed paint on their airplanes to show who they were. I suppose I could go look it up in the archives. There's the chance I could find him in some gruppe's log book, having flown on this particular day, in this particular place, a few miles northwest of the French town of Strasbourg that sits on the Rhine. There are fellows who've done that, gone back and looked up their opponents. I never have. I never saw any point.

He was someone who was trying to kill me, is all.

So I'm looking back, almost straight down now, and I can see this 20-millimeter cannon sticking through the middle of the fighter's propeller hub. In the theater of my memory, it is enormous. An elephant gun. And that isn't far wrong. It is a gun designed to bring down a bomber, one that fires shells as long as your hand, shells that explode and tear big holes in metal. It is the single most frightening thing I have seen in my life, then and now.
(...)Clarence "Bud" Anderson.

The whole story is HERE (http://www.elknet.pl/acestory/anderson/anderson.htm).

So, it was not Gentile after all...:kilroy:, but the rest of the story is pretty much what I said.

Ivan
September 3rd, 2010, 18:37
Hello Hubbabubba,

I have seen that story from Bud Anderson from other sources. I have also met the man at a local Gun Show in Maryland. I believe he was trying to sell his book at the show.

What I can tell you is that there are many men who can fly VERY well and aren't necessarily the most reliable source for aeronautical information. I can tell you for a fact that you cannot see the muzzle of the gun that is installed as the motor cannon on a Me 109. What you see is a blast tube through the spinner. The actual muzzle is several feet behind which is why I don't believe you can see the muzzle flash. Perhaps you can tell which gun is installed by the sound of the jackhammer.

I am pretty sure you know that the 20 mm version of the motor cannon in a Me 109G (MG 151/20) and later was not a particularly powerful weapon. Instead of just the one on a 109G, the FW 190A carried FOUR of the same type of gun. It wasn't bad, but it wasn't any better than the Hispano that British fighters mounted. The 30 mm MK 108 was a much more devastating gun.

I still wonder though: If the German could really fly which Anderson states AND had a better plane. The power to weight ratio and climb rates of the later 109s was such that in a vertical climb, the Mustang should not have a chance. As we all like to say, it is the Pilot and not the plane, but then again, sometimes it IS the plane that makes the difference.

- Ivan.

Ivan
June 3rd, 2011, 04:36
This thread came up as related with the AF99 Tutorial I am working on. This discussion about what can actually be seen on an aircraft seems to be the perfect place to discuss what to include and what not to include in an aircraft design. Some things are necessary because they are the recognition features of the aircraft. Some things are so small that they are not really noticeable.

- Ivan.

hubbabubba
June 3rd, 2011, 12:28
This is quite a "thread revival", Ivan! LOL!:icon_lol:

I don't know if Bud Anderson was seeing the hole in the propeller hub, the blast tube within or the actual 20mm muzzle, but what he saw made an indelible impression on him. Firearms have a tendency to do that when they're pointed at you. It was probably not as potent as an Mk 108, but the anticipated effect is the same; sheer terror!

The biggest caliber I ever had pointed at me was a BB gun, but I have a vivid mental image of that little black hole, curve inward at the perimeter with stamped inscriptions around, and the a$$hole shooting at me was a good twenty feet away! I guess my imagination ran wild as I was charging him to snatch it from his hands and break it on the nearest tree trunk.

Same thing with the black pick-up that almost killed me. I do remember vividly the shiny grille, the yellow-amber-white plastic spotlight cover, the black luster finish of the paint, but I would be incapable of telling you if it was a Ford, A GM or a Subaru!

Details are frequently different for different observers depending on their physical and psychological point of view.

Ivan
June 4th, 2011, 15:51
Hi Hubbabubba,

Yes, that was a great revival. I was bringing up this thread again because the original discussion was about what could be seen in a CFS model. My point was that the gun muzzles in a typical fighter aren't all that visible no matter what the perception is in combat. We modellers whether electronic or plastic try to emphasise certain details that just don't stand out in photographs of aircraft. How often can you see the rivets and panel lines on an aircraft that was flush rivetted if you are standing more than 20 feet away? Can we see a Radio Antenna? Fuel Cooler? Canopy Latch? In general, most of this stuff is invisible at the distances that we see other aircraft.

- Ivan.

hubbabubba
June 4th, 2011, 23:11
Hi Hubbabubba,

Yes, that was a great revival. I was bringing up this thread again because the original discussion was about what could be seen in a CFS model. My point was that the gun muzzles in a typical fighter aren't all that visible no matter what the perception is in combat. We modellers whether electronic or plastic try to emphasise certain details that just don't stand out in photographs of aircraft. How often can you see the rivets and panel lines on an aircraft that was flush rivetted if you are standing more than 20 feet away? Can we see a Radio Antenna? Fuel Cooler? Canopy Latch? In general, most of this stuff is invisible at the distances that we see other aircraft.

- Ivan.

This is why I added LOD models in my jeeps, like stock a/c. As you say, at twenty feet, you don't see the rivets, but if you go for a spin in your favorite mount, this is the kind of details that get you "immersed", well... at least... it does the trick for me!:cool:

The added bonus with LOD is that it is framerate-friendly, which also helps the overall experience.

I understood your "revival" question. I was simply pointing out that what is detail for some is not for others. This is all too obvious in the 3-views I (and, no doubt, you too) collect on the web and elsewhere. One artist will put great emphasis on reproducing, let's say, the gills of an air intake while missing completely the riveting pattern of an under-wing, and another will take great care of this later aspect but only sketched the air intake.

Photos may help, but not always. The camera don't think, but film sensitivity, aperture, angles, lightning will influence what we see. I'm always astonished by the human eye and its ability to perceive things that elude the best camera. One example that anyone can relate to is the classical case of the failed attempt to capture the picture of some animal at the zoo that stand in the shade in a bright afternoon. Our own eye sees perfectly what will turn into a black hole in a sunny blur when you get your film developed.

Devil is in the details...:angryfir:

Well... what I'm trying to say is that, as a modeler, we do have to stop somewhere but, at the same time, I can't help but notice that I never received a negative comment about being too detailed! smilo may have contented himself with a less elaborate model, but he never complained of having a too good one to play with! At least, that is my interpretation...

smilo
June 5th, 2011, 05:11
Devil is in the details...:angryfir:

Well... what I'm trying to say is that, as a modeler, we do have to stop somewhere but, at the same time, I can't help but notice that I never received a negative comment about being too detailed! smilo may have contented himself with a less elaborate model, but he never complained of having a too good one to play with! At least, that is my interpretation...

well, there's the rub, isn't it?
you have never heard me,
or anyone else for that matter,
complain about too much detail.

BUT, at great risk, i will complain,
that projects don't get completed
because of some minor detail,
or dwindling interest caused
by some minor detail,
that most would never see.

Ivan
June 19th, 2011, 05:50
I have never received criticism for being too detailed but then again, I have never received criticism for not being detaile enough either. For that matter, criticism is pretty rare in this game.... You would think that all the aircraft built were superb models for this reason, but we all know that is not the case.

- Ivan.

smilo
June 19th, 2011, 06:23
For that matter, criticism is pretty rare in this game.... You would think that all the aircraft built were superb models for this reason,....

well, i guess i haven't been
blunt enough or loud enough.

PLEASE SHOW ME A DECENT
A-20, B-25, B-26 or Do17

and that's just for starters.

i mean for cryin' out loud.
how many flippin' P-51s
are out there?
sure, it was a great plane,
but give me a break.

if you will remember,
this forum use to be
bitch central.
nearly everyone was a critic of sorts.
the reason you don't see it anymore
is that people have moved on,
be it developers or clients, ie critics.
you should drop into the FX forum sometime.

Ivan
June 19th, 2011, 19:23
Hi Smilo,

This kind of message was why I started the "Conspicuous By Their Absence" thread way back.

I see you like the medium twins. I can't disagree with you that there aren't very good examples of those planes out in the wild. The problem is that to do one of these things well hits right at the limit of what AF99 can do. To do it properly really requires SCASM and there aren't that many folks who work well there.

Besides the planes you mentioned, I can think of a bunch more I would like to see and fly in CFS:

1. J2M Raiden
2. Kawasaki Ki-61
3. N1K2-J Shiden KAI
4. F4U-1 Corsair
5. F2G Corsair
6. Me 309
7. Ju-87D Stuka
8. He-177 Greif
9. SBD Dauntless
10. F8F Bearcat
11. Ki-43 Hayabusa

The list goes on..... Some of these planes aren't all that hard to build.

- Ivan.

smilo
June 20th, 2011, 11:52
no doubt about it,
i do like medium twins.

i just finished a FS9 tour in a C-46 and an A-20.
now, i'm preparing for another.
i'm waffling between the C-46, again,
or the C-119, or maybe even the C-82.
i've got a week to decide.

the me-309 is sure interesting.
as you know, i spent a fair amount of time
trying to build that one to no avail.

as for scasm, like everything else for me,
the learning curve is pretty steep
and my time is pretty much taken up.
it's not that i wouldn't like to learn it.
i just don't know when i could find
the time to devote to it.

hubbabubba
June 21st, 2011, 10:15
(...)
well, i guess i haven't been
blunt enough or loud enough.

PLEASE SHOW ME A DECENT
A-20, B-25, B-26 or Do17

and that's just for starters.

i mean for cryin' out loud.
how many flippin' P-51s
are out there?
sure, it was a great plane,
but give me a break.

if you will remember,
this forum use to be
bitch central.
nearly everyone was a critic of sorts.
the reason you don't see it anymore
is that people have moved on,
be it developers or clients, ie critics.
you should drop into the FX forum sometime.



(...)
as for scasm, like everything else for me,
the learning curve is pretty steep
and my time is pretty much taken up.
it's not that i wouldn't like to learn it.
i just don't know when i could find
the time to devote to it.

I will do a Boston III smilo, and it will be SCASMed. How much clearer can I get?:kilroy:


(...)
To do it properly really requires SCASM and there aren't that many folks who work well there.
:redfire::redfire::redfire: