Gloss map is basically a roughness map, it always has been!
It might be getting renamed for these new PBL engines for the sake of being clear on what it does.
our engine uses "cosine" maps which are pretty much gloss maps, except they take specular intensity and glossiness into account. so instead of dealing with 2 maps, you only deal with 1.
I wouldn't skip metalness, especially since it's so easy to make. It's just a black and white map with no dithering to define conductive and dielectric materials.
^
Metalness will make the difference between an anodized colored metal and piece of plastic. Its crucial to use to define your surfaces.
gloss and roughness maps perform the same function to the artist. but the way they are calculated internally are both very different. and, more to the point. roughness has a finite value, whereas gloss doesn't.
for example, gloss maps allow you to input a value between 0 and 1. this is then interpolated to between 0 and x, where x is the value you want it to be.
that works fine for the way gloss is calculated, and certainly it allows you a little more artistic control. but it doesn't work for roughness, where the input value of 1 is then mathematically calculated to give you the maximum known measured falloff.
so no, the map isn't going away. but you can expect the results from the map to be a little different in the future.
that's not true. if you think about a physical surface, there's not really a limit to how rough it can get. and sure enough, most specular distributions take roughness values up to infinity. the map still does the same thing it has always done (controlling specular distribution).
that's not true. if you think about a physical surface, there's not really a limit to how rough it can get. and sure enough, most specular distributions take roughness values up to infinity. the map still does the same thing it has always done (controlling specular distribution).
In the ibl engine I've used, roughness over a value of 1 has no effect. In other words, it takes working values of 0 - 1.
that's because if you take the value over one, you start getting lighting artifacts, because the light diffuses further than is physically possible.
another way to look at it, is the angle at which light can be seen to reflect from the surface, which does go to a limited value. http://en.wikipedia.org/wiki/Glossmeter
so think of a roughness value of 0 as light reflecting to within 20 degrees of the source, and 1 being no greater than 90 degrees from the source. if you go over one, the light inverts on itself, hence causing artifacts in a game engine.
So many names... on planetside we would make both metallic and dielectric maps. I think dielectric could be another name for roughness or gloss. not sure though
Yeah in my experience pure black and white are to be avoided as they created artifacts. I just put a levels adjustment layer over the roughness map and bracket the output values inward a bit, so instead of having 0-255 you would have 2-253.
yea thats the general process i use too.. mostly though because once an object goes into the engine, if it has pure black/white in the textures, then you go in with post process, those values would get crunched and not look right.
Replies
It might be getting renamed for these new PBL engines for the sake of being clear on what it does.
^
Metalness will make the difference between an anodized colored metal and piece of plastic. Its crucial to use to define your surfaces.
not really.
gloss and roughness maps perform the same function to the artist. but the way they are calculated internally are both very different. and, more to the point. roughness has a finite value, whereas gloss doesn't.
for example, gloss maps allow you to input a value between 0 and 1. this is then interpolated to between 0 and x, where x is the value you want it to be.
that works fine for the way gloss is calculated, and certainly it allows you a little more artistic control. but it doesn't work for roughness, where the input value of 1 is then mathematically calculated to give you the maximum known measured falloff.
so no, the map isn't going away. but you can expect the results from the map to be a little different in the future.
In the ibl engine I've used, roughness over a value of 1 has no effect. In other words, it takes working values of 0 - 1.
another way to look at it, is the angle at which light can be seen to reflect from the surface, which does go to a limited value.
http://en.wikipedia.org/wiki/Glossmeter
so think of a roughness value of 0 as light reflecting to within 20 degrees of the source, and 1 being no greater than 90 degrees from the source. if you go over one, the light inverts on itself, hence causing artifacts in a game engine.
yea thats the general process i use too.. mostly though because once an object goes into the engine, if it has pure black/white in the textures, then you go in with post process, those values would get crunched and not look right.