AlphaSim transparencies..

[oldwheat]

....Can someone give me a mini-tutorial as to how the tranparencies are accomplished on certain AlphaSim aircraft, in particular, the freeware B-25J...It doesn't seem to be a standard Alpha channel application & uses 2 identical appearing bmp.s plus another for the interior view.....
.....I'm thinking that this process could possibly be very useful for other aircraft with opaque tranparancies unless of course, it is mapped to the mdl. file in some way.....

[Serval]

Can you show what the both files look like in Photoshop? Maybe one of us gets an idea.

[adlabs6]

Hmm, I've not handled these files so I can't say for sure. Is one of the bmp's designated as "alpha" or "transparent" ? Do the textures contain any alpha layer at all?

From what I recall, trasparency doesn't need to be set in the mdl file, as any alpha in the texture will automatically turn the model trasparent, like you said. It may be that they used a chroma trasnparency, I've never seen this in an FS model, but it might be possible.

[oldwheat]

......Both bmp.s are identical in appearance. One is named= 'glaz.bmp' & is 8 bit..The other is named='glazx.bmp' & is 24 bit....Neither shows an Alpha channel in DXTbmp.......

[adlabs6]

It looks like the window areas are the gray color in that image. Try using a test bmp that is solid in RGB value of that gray, and see if the window area changes (in fact, the entire nose of the plane may be invisible!)

If there is no change, then its probably not a chroma transparency. In this case, I can only guess that the windows are built in the model at a preset transparency (but still a little visible) and that the glaz.bmp files are used to apply a texture to the faintly visible glass. You can test this by putting a checkerboard texture as the glaz.bmp and see if the windows show the checker pattern.

[oldwheat]

.....Yes, the checker patterned bmp. does show up on the glass.....I can do what is an apparently identical bmp. save it (with the same gray RGB) in extended 256 bit & get a texture which looks identical, is the same size, the gray color hasn't shifted, etc..But the damn tranparencies are still opaque!!....Frustratin' as hell!.....I'm using Paintshop, do you think that may possibly be the problem??.......BTW, there is also a third bmp. pretty much identical to GLAZ.bmp called 'glazint.bmp'....If I flood the other 2 bmp.s with color. it doesn't seem to have much of an effect, if any.....All the action seems to be in the 'glaz.bmp', not even sure WTH the other 2 are for

UPDATE: Seems that there must have been an alpha channel involved after all....Added one to the 'GLAZ.bmp' and it worked just like the original...Stilll have no idea what the other two bitmaps are for but 'If it ain't broke, don't fix it'...Thanks guys.....

[adlabs6]

Ah, well glad you solved it. I suppose that on the bmp which shows checkers on the glass could be used to create some wear or dirty window edges.

[oldwheat]

...Say, that's a thought.....different shades of gray in the alpha texture might make for some interesting effects .....