Well i have read a lot about this in the forums.
An image with embedded alpha channel cant be used directly both as diffuse and opacity map.
If you try to do it max can actually read the alpha channel and apply as opacity BUT is like they get the greyscale of that map messed up.
The whites are not treated as whites and asume that blacks neither, cause there are some semitransparent parts where there should be completely opaque ones.
It ocurres to me that has something to do with a gamma issue (no clue) is just i have been reading a lot about filmic tonemapping and how shaders are writen and there are a lot of issues if the gamma correction is applied and where is applied. (I'm not expert whatsoever just generalist curious talking so dont kill me).
So i wonder... if there is a way max can output a channel out of a image like just R, G, B ,A values? so i can experiment with just the alpha channel of the image?.
The answer is yes, the ColorCorrect node has an option to output selectively a channel of your choosing.
Perfect.
So i created a material with a targai image that has alpha channel and put the map to both diffusse and opacity. As expected the opacity are interpreted in a distorted fashion as always. And every combination of the alpha interpretation that max have just make it worse.
So i lineup a colorcorrect node between the texture and the opacity, i let only the alpha channel trough... in the preview looks like a normal map no issues there but behaves differently.
So next step i choose advanced and try to counter the gamma (i asume got messed up double time).
As no expert whatsoever i try correct to 2.2 using the slider... not enough. So i instintively bumped til 4.48 (2.2x2.2 cause it could be that gamma where applied twice somewhere... ) and it works like intended.
So my question for the technician experts or anyone who knows.
Is this a Corona related bug interpreting the gamma of an image format... like puttin (1/2.2) in a weird place?...
Is this a completely unrelated to gamma and i just get lucky?...
Is this a Max issue?... cause in other places they claim that Vray doesn't have this problem.
THe post that gave me the idea to mess with gamma was
http://filmicgames.com/archives/75 and was related to a discussion here on forums by Juraj about tonemmaping
Greeting from Chile.
PS: The image has a 1000 as gamma correction cause was my first try. Dont take that number in account it should say 4.48.
PS: i know its a known bug or limitation just i'm wonder if this could be a solution or i'm tottaly off rails. XD.