How light affects materials?

[frizDog]

you could do a few different things...
but what i think you are asking about is translucence. . .the red in an ear that is backlit is really subsurface scattering. Cloth doesn;t really have much of that.

I would try putting a point light under the cloth that is light linked only to to the cloth . .
Cloth needs a little translucence as well.

what renderer are you using?

[MrMJKnight]

what renderer are you using?

Ah!


Im using Mental Ray with Final Father + Global Illumination.

[frizDog]

With mental ray you should be able to turn on incandescence for the sphere and it should start to light up that cloth

[MrMJKnight]

Oh right, where would I find Incandescence?

[frizDog]

can't help you there..i haen't opened mental ray in a while. . .im sure someone else in this forum, or the help documents will point you in the right direction

[MrMJKnight]

Aww.

Thank you, very much appreciated for your help =)

[playmesumch00ns]

you could do a few different things...
but what i think you are asking about is translucence. . .the red in an ear that is backlit is really subsurface scattering. Cloth doesn;t really have much of that.

Errr... yes it does. Cloth fibres are usually highly translucent.

You could either use full-blown subsurface scattering or use a traditional 'reverse-diffuse' approach (in most renderers this is usually called simply 'translucence' and just does a normal diffuse calculation but looking the other way). The 'translucence' approach is normally more beneficial for cloth since it's often thin enough that you don't really need a full-on sss solution.

Either way you're going to want to modulate the effect with a weave texture to give the impression of layers of fibres.

Here's an example of what I mean:
http://www.flickr.com/photos/75304241@N00/988248218/

See how the light's bleeding through the curtain and you can clearly see the weave of it in the bright parts.

You might also want to use a very fine-detail opacity texture, again with a weave pattern, since you can often see straight through gaps in the weave. You'll need to raise your sampling up quite high if you do this though in order to capture the pattern without aliasing.

[MrMJKnight]

Thank you for the reference! =)

Helped me a lot,

I've redone the cloth sim, and worked on the opacity texture.

I think it looks a lot better than before, the only thing is I think it's slightly a bit too see through where the cloth is touching the ground surface.

Here's an update.

http://www.martinjknight.com/cgsociety/studio_lighting_postprocessed_03.jpg

And here it is, before.

http://www.martinjknight.com/cgsociety/studio_lighting_postprocessed_02.jpg

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