How to texture eye glasses?

Timidy

I want to know how I should texture a pair of glasses that my character will wear that will work for a game engine like Unity or UDK. Should I separate the frame from the glasses or is it ok to have it all as one mesh? Also, do I create an alpha map for the glass portion?

EarthQuake

Separate the frame from the glasses, you want to use alpha blending on as little geometry as possible. Also its probably best to have a separate texture for just the transparent bits too.

If these eyeglasses will always go with one character, put the frames with the main texture map for the character, and put the lenses on a separate, small texture.

Timidy

OK cool EarthQuake thanks. Shouldn't the entire lens portion of the glasses have alpha maps? 512x512 should be ok for the lens textures then right?

EarthQuake

The lens elements and those alone should have an alpha map on a smaller texture. 512x512 is probably a little large but I don't know how big the rest of your textures are, even if the character's head is filling the frame at 1080p, the lenses of the glasses probably won't take up 512x512 pixels.

The reason why you want a separate, smaller texture is because when you take image compression(DXT) into consideration, having and alpha channel doubles the memory used. So using a 32bit 2K texture is like using 2 24bit 2K textures.

Timidy

Thanks EarthQuake, that's good to know. So it's a good idea then to always have transparent objects as their own objects. What about if you keep it a single mesh and just assign different material id's, would that be the same as having a different texture?

512x512 is too large you're right. I'm very new to game textures and while exploring the RE6 game files I saw textures as small as 64x64. I guess they don't have to be large depending on what it is.