[Sidefx-houdini-list] translucent backlit surface

Larry Giunta larry at gcreativestudios.com
Thu Mar 3 16:56:29 EST 2016

Hello all, 

I’ve used a technique in the past to create a backlit glass or plastic surface.
Similar to the buttons on the old Simon game … or a lit traffic light or light table.

I was able to “reverse” a flat surface with the primitive SOP.

Then, in a regular mantra material node, I could simply pipe a “negate” node 
into the “I” input of the “surfaceModel” node.

If I then placed a point light behind the surface I would get the backlit effect.

This still works for me if I go back to H13.

But in H14 or H15 I only get a solid black or dark grey surface.

I’m assuming something has changed within the basic operation of the shader or mantra.
I’m hoping I can fairly easily recreate this effect in H15. But I’m coming up short so far.

If anyone has any suggestions I’d greatly appreciated the input.



Larry Giunta 
Creative Director
G Creative Studios

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