i am watching the cmivfx dvd about shading and rendering on Houdini…and they are making a translucency shader by inverting the normals of the surface in the vops…
I've copied exactly the same steps but i cant achieve the same result that they do….

I'll add the HIP file so you guys can try it…

When working with shaders that disable the frontface() call in Mantra that ensures faces always are oriented correctly, you have to manage your primitive normals.


The Primitive normals now drive the directionality of the surface. Turn on display of the primtive normals and you will see that they are pointing towards the light.

Either bypass the Negate VOP, re-orient your primitive normals by rotating the grid 180 degrees, or use a Reverse SOP to flip the primitive normals.

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This issue always comes up with two-way shaders, shaders that use translucency and glass shaders that refract. No worries. It catches everyone at some point. I really wish Houdini had a feature like what SketchUp has where you can clearly see when you are looking at the backface of a surface…