What to do with the MiG's alpha?

[SSI01]

I remember seeing the explanation for this in the past, somewhere - the texture's got an alpha file I think I need to get rid of. I have DXT.bmp and IrfanView. I was toying with keeping one copy of it because it does a fine job of showing how a centrifugal-flow jet engine is mounted in this fighter. The texture is for the Bear Studios MiG-15bis and is an add-on with the pilot in a modern hard helmet plus flying casual in a "Brietling" shirt.

[Mick]

I can't tell from your screen shot if the engine image is in the alpha channel or painted onto the external skin on the main texture.

You can tell by opening the texture file in DXTbmp. You'll be able to see if it's on the main texture or the alpha channel.

If it's painted on the main texture, you'll have to paint it out.

If it's the alpha channel letting you see inside the fuselage to the engine, then you'll see a darker part of the fuselage image on the alpha channel. If that's the case, just make that part the same shade - presumably all white - as the rest of the fuselage.

I suspect that the image is painted into the fuselage. Why? Because that natural metal skin cries out for reflective textures, an I would expect someone like Bear Studios to make the model reflective. But maybe not...

Anyway, if reflections are enabled in the model, then the alpha channel controls the degree of reflectivity and not transparency. (You can't have reflection and transparency in the same model at the same time.) You'll know which it is as soon as you look at the texture in DXTbmp.

[SSI01]

Thanks Mick, I'll take another look at that texture.

EDIT: Here's a screenshot of the pertinent texture file in the aircraft's folder. If I'm interpreting this correctly the engine is indeed painted into the main texture and, as you said, it looks like I'll be painting it out. Alpha is in the top right corner.

[Milton Shupe]

Looks like the mig2_t.bmp is used for the wings. Where's the fuselage texture sheet?

Normally when the bmp does not use the _t, then alpha is used for transparency as with a prop or glass texture.

However in this case, since the _t is used, my bet is that the model's materials for fuse and wing have transparency set in the model.

[SSI01]

Here's the MiG's fuselage texture:

[Mick]

It looks like the engine is painted on the top view texture file but not the side view texture - yet it's visible on the side of the fuselage in the sim. The top view texture shows that it's not done with the alpha channel.

This makes no sense to me at all. I'm afraid I'm all out of ideas!

[SSI01]

That's disconcerting. What looks like it might be engine textures on the top of the side textures is actually part of the intake (I think) plus flap textures. So what's in the top-down texture file is the engine after all, as I thought. This is a stumper.

I will try to find that texture again, I think it's at flightsim.com. Time to look up the maker of the file and describe my situation to him.

[AckAck]

It appears that the alpha channel controls transparency , not reflectivity. What you are seeing is a partially transparent fuselage revealing the details beneath. I'm assuming that if the alpha channel is replaced with solid white, the problem will disappear. It also means that the model isn't set up for reflectivity, unfortunately, as Mick and Milton have both mentioned.

[Milton Shupe]

It appears that the alpha channel controls transparency, not reflectivity. What you are seeing is a partially transparent fuselage revealing the details beneath. I'm assuming that if the alpha channel is replaced with solid white, the problem will disappear. It also means that the model isn't set up for reflectivity, unfortunately, as Mick and Milton have both mentioned.

I looked at the fuselage texture posted above and not sure that is the actual named texture in the texture folder so I could not say for sure what is happening.

Note the name of the texture; poorly displayed but the name doesn't look right. The wing texture shows as Mig_1_t.bmp but the fuse texture seems to read Mig_1Xt.bmp instead of Mig_1_t.bmp. That example may have been a temporary bmp. I would like to know what the actual name is from the texture folder that was used in the first screenshot at top of the thread.

[Willy]

It appears that the alpha channel controls transparency , not reflectivity. What you are seeing is a partially transparent fuselage revealing the details beneath. I'm assuming that if the alpha channel is replaced with solid white, the problem will disappear. It also means that the model isn't set up for reflectivity, unfortunately, as Mick and Milton have both mentioned.

Ran into pretty much the same thing years ago with a Paul Rebuffat Spitfire texture. It was for a highly polished post war Spitfire and took a special model for the reflectivity. If used with one of his regular models, I got the "glass skin" effect. I suspect that with this Mig, the textures aren't supposed to be as shiny as that Spit was so it isn't as see through as the Spit was.

Edit: I was a bit surprised to find out I still have that Spitfire in FS9. Here are some shots of it's textures in DXT/Bmp





Note how much darker the alpha channel is in the upper right corner of DXT/Bmp than the shots of the Mig posted earlier. I'm pretty darn sure that if the alpha layer is removed, the transparency will go away.

[SSI01]

Let me post the original textures.



I should have mentioned this texture was originally made for FSX use. However, take a look at its properties, in the upper left; they are the exact same as for the FS9 Mig (i.e., no image flip or other alteration required). I've run them through DXTBmp as you can see and their positioning is exactly the same as their appearance in the FS9 textures. I've also attached an enlarged alpha channel for the fuselage of a MiG-15 add-on texture that is already in the sim and functions perfectly. There appears to be considerable difference between this alpha and that for the texture in question. I suppose this might be a good time to think about exporting/importing this alpha channel from the other MiG to this one.

[Willy]

If you accidentally use a flipped texture, you can't miss that fact. Don't ask how I know... LOL

[SSI01]

Yeah, I wonder how I'd notice . . .

[SSI01]

Took both alphas from another texture of a MiG on the US airshow circuit, and used them to replace the alphas that came with the Breitling texture. I'm on the right track, I think, but there's still some artifacts from the other texture in the new alpha.