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Transparent Emitters and Multilight

Posted: Mon Oct 12, 2009 7:21 am
by punkhaus
I'm attempting to render a display with multiple "screen" graphics in it so I can cut down on multiple renders.

Is there a way to "gang" these up via turning an emitter transparent so that when it's off in multilight the ones behind it show up instead? I've tried a number of different settings, but it doesn't seem to have an effect.

If they are on the same plane, maxwell will split them on the triangle and i'll get half of each.
If they are out of sync in depth, the top one only will show up.

Any thoughts? :?:

Thanks!

Re: Transparent Emitters and Multilight

Posted: Mon Oct 12, 2009 9:46 am
by macray
I think Mverta describes in his Stacked Material video (on Think.maxwellrender.com) a way to an emitter that when switched off shows the materials underneath. Maybe you just put all the emitters one atop the other in one material and switch them off one ofter the other (maybe just in the end...).

I'll give it a try...


edit: haven't found a solution with this. If I have more than one emitter layer in the material it will just show up as Multi-emitter, but I have no control of the separate emitters.
Otherwise
- setting up 2 materials -light1 and -light2 (each using a transparent BSDF and an emitter layer)
- assign light1 to the screen and light2 to a copy of the screen (to separate the different emitter pictures)
=> resulting in the same triangle problem.
I thought that switching off one emitter would only show the transparent part of the material and the other emitter would show up but only one part of the screen triangle shows the other is black. When both emitters are switched on it shows half the screen light1 and half the screen light2 according to the triangles.

Re: Transparent Emitters and Multilight

Posted: Mon Oct 12, 2009 1:52 pm
by Mihai
punkhaus wrote: If they are out of sync in depth, the top one only will show up.
You can make an emitter become invisible when it's off by adding a BSDF component to the emitter material, setting ND to 1 and transmittance to 255. In this case it's a completely invisible material, but when the emitter is turned on, it will show the emitter in the render. Turn it off and it becomes invisible, showing the emitter in your plane underneath.

Re: Transparent Emitters and Multilight

Posted: Mon Oct 12, 2009 2:23 pm
by macray
Thanks Mihai.

This works fine if the planes slightly shifted and don't use the same space.