Transparency Tests for FS9 Only
Results 1 to 5 of 5

Thread: Transparency Tests for FS9 Only

  1. #1

    Transparency Tests for FS9 Only

    Transparency Tests For FS9 Only

    I have seen many discussions about transparency and it is hard not to
    be confused by this topic in FS9 or FSX.

    MS FS9 SDK's do not clarify anything on this topic but strangely only
    seem to confuse the matter.

    When to use glass_t.bmp versus glass.bmp and what does that _T really
    do?

    And, what about makemdl's options concerning "HasReflectMap" and
    "HasLightMap" have to do with this aside from adding more confusion.

    I am using variations of a glass.bmp texture for these tests.
    The primary color for all textures is always darkgray at 55,55,55.
    I vary the alpha channel to change appearances and transparency.

    So, the fact is that you can use either glass_t.bmp or glass.bmp but
    you must treat them differently in gmax.

    Glass_t.bmp requires that you set opacity in gmax at your desired
    transparency level. I use 50% opacity for the glass_t.bmp side of the
    test.

    To test the Glass.bmp (no _t), I use 100% opacity and vary the alpha
    channel darkness to get more or less transparency.

    I use a specular level setting of 37 for both tests to get sun glare.

    Here is the setup:

    Glass.bmp Opac % Alpha ---- Glass_t.bmp Opac % Alpha
    --------- ----- ----- ---- ----------- ----- ------
    glass1 - - 100 - - 200 ---- glass1_t - - 55 - - 230
    glass2 - - 100 - - 150 ---- glass1_t - - 55 - - 200
    glass3 - - 100 - - 125 ---- glass1_t - - 55 - - 170
    glass4 - - 100 - - 100 ---- glass1_t - - 55 - - 140
    glass5 - - 100 - - 075 ---- glass1_t - - 55 - - 110

    This test shows that glass.bmp (no _t) uses the alpha channel
    effectively to control transparency.

    It also shows that specular setting of 37 operates equally well to
    yield sun glare with both techniques.

    So, what is the glass_t technique doing differently?

    The effect of using the _t and darkening the alpha channel seems to add
    more reflective glossiness. In doing that, it effectively decreases
    the appearance of transparency as if the glass is becoming more
    mirror-like as the alpha channel goes darker. It's an interesting
    effect depending on your needs. However, you can retain much of that
    mirror-like look while increasing transparency if you go back to gmax
    and reduce opacity to say, 40% instead of 50%.

    I also found that makemdl export option noted above ("HasReflectMap")
    have some bearing on these results.

    By unchecking that option, it eliminates the glossy reflection; the alpha channel is then used to
    control the transparency beyond the 50% opacity stated in gmax. I
    recommend that you leave the reflect option turned on.

    In summary, the glass.bmp using the alpha channel to control
    transparency is the effective and recommended basic approach.
    However if your project requires a glossy-like or mirror-like, transparent
    window or surface, you can use the glass_t.bmp approach in conjunction
    with a lowered opacity setting for the material in gmax.

    Keep in mind that a glass_t.bmp (or any use of _t) with 100% opacity in
    gmax and a dark alpha channel will get you chrome.

    I hope this test clears up some things, and helps spur some thoughts
    and experimentation for you.

    I am including the gmax source and bmps for you should you wish to run your own tests.
    Milton Shupe
    FS9 Modeler Hack

    Video Tutorials - Gmax for Beginners My Uploads on SOH

  2. #2
    Thanks, great job.

    Then there is the issue of what these FS9 materials do in FSX. In my experience, the materials using only Opacity will be invisible (clear) in FSX, while those using only the alpha channel will look the same. I always use 99% Opacity in those cases, so GMAX knows to order the parts correctly.

  3. #3
    Quote Originally Posted by tgibson View Post
    Thanks, great job.

    Then there is the issue of what these FS9 materials do in FSX. In my experience, the materials using only Opacity will be invisible (clear) in FSX, while those using only the alpha channel will look the same. I always use 99% Opacity in those cases, so GMAX knows to order the parts correctly.

    Excellent point Tom. I thought I said that but in review, I guess I did not.

    They do become invisible when clouds and other alpha based materials come into play.

    If you plan to port over to FSX, use 99% opacity for your gmax material settings and totally control transparency with the alpha channel.

    That's something I keep forgetting to do for both glass and blurred props.

    EDIT: Tom, I just converted my CANT Z.1007 to use 99% opacity and a darker alpha for glass.bmp. The glass disappears as always and does not have as nice an appearance without the "glossiness" to highlite the fact that it is glass and the specular lighting is almost non-existent. So, I am uncertain how you keep the glass from disappearing. Any help in clarifying the issue is appreciated. Might it be because I have reflect map turned on in the makemdl options and there is no reflectmap?

    EDIT2: NO, I tried HasReflectMap off and that simply turned the glass to opaque-like skyblue chrome. :-) I reverted back to what I had originally (glass_t.bmp) as the 99% opacity with the glass.bmp alpha controlling the transparency made the glass look dull with less shine. If you have any suggestions, they will be appreciated.
    Milton Shupe
    FS9 Modeler Hack

    Video Tutorials - Gmax for Beginners My Uploads on SOH

  4. #4
    well, all fs9 glass in fsx is going to be a compromise, and will not be as good as true fsx glass.

    try making the alpha channel lighter until you get some 'substance' in the glass

    ps. shift key not working...

  5. #5
    Quote Originally Posted by tgibson View Post
    well, all fs9 glass in fsx is going to be a compromise, and will not be as good as true fsx glass.

    try making the alpha channel lighter until you get some 'substance' in the glass

    ps. shift key not working...
    Thanks Tom. Will check that out. :-)
    Milton Shupe
    FS9 Modeler Hack

    Video Tutorials - Gmax for Beginners My Uploads on SOH

Similar Threads

  1. Transparency question
    By oldwheat in forum The Paint Shop_Skinnin' Your Game!
    Replies: 3
    Last Post: January 31st, 2012, 16:02
  2. FSD Cessna 0-2 transparency issues in FSX
    By roger-wilco-66 in forum FSX General Discussion
    Replies: 3
    Last Post: September 28th, 2011, 04:40
  3. Freeware FSD T-38 transparency fix
    By OBIO in forum FS 2002/2004 General Discussion
    Replies: 12
    Last Post: October 11th, 2010, 20:19
  4. Cockpit Transparency
    By TARPSBird in forum CFS2 General Discussion
    Replies: 4
    Last Post: September 15th, 2010, 18:30
  5. Glass transparency colour.
    By SirBenn21 in forum FSX General Discussion
    Replies: 6
    Last Post: April 21st, 2009, 11:36

Members who have read this thread: 21

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •