I have been putting together a grass material, and my results so far are what I’m looking for. The problem is when a shadow is cast onto the grass it appears that there is no subsurface effects. Any ideas on what could be causing this?
It’s not as easy to see it in the pictures…but it looks horrible. There are black areas and its almost as if all of the color has been taken out of it. I think the black areas are being caused by my normal, but I can’t figure out why. I’m not a big fan of posting my materials, but here are the relevant parts.
A better image showing the issue would be great. However SSS will only work when the surface is directly lit because it’s calculating how much light passes through when the light source is on the other side of the surface. If there is no light source visible then you won’t see SSS. Light probes provide a generic, surrounding light environment so they can’t be used in the calculation even if they are present.
Subsurface not working without the direct lighting I guess makes sense. What would you recommend doing to resolve the issue? I have noticed that when I turn subsurface off altogether that I get a similar look…perhaps its just showing what my material looks like without subsurface? So in order to troubleshoot it I should work on getting it to look good without subsurface before adding it for the lit areas. What are your thoughts on this?
I’d add a very faint green emission to make the dark areas less ugly. Of course it will increase brightness of lit grass too so you might want to darken the diffuse color to compensate. It would be nice to apply this emissive only to pixels in shadow but I don’t know any nodes which would get that information. (The LightVector doesn’t work in the Surface material domain.)
Sorry I figured less stuff would make it easier since subsurface was not affecting the shadowed areas. It actually does seem to change the black areas to a green color, however its washed out. The level of detail from the lit area to the shaded area is totally different.
Perhaps tone down the emissive a bit, low enough so it doesn’t make the lit areas glow but high enough to remove pitch black pixels in the shadow. Try to find the middle ground between the two kind of ugly.
Or you could try to use the new light channels. I haven’t tried this so I’m just speculating but if you could make a faint, shadowless distant light which only affects the grass then that would help too. That “grass filler” would provide subtle directional lighting even in the shadows of other lights.
Well here is the best so far. It def. looks better, but I really wish I could get more depth. It would be nice if I could adjust AO in only shaded areas.
