Single-sided materials?

Jalnor

I've been fighting with a custom object for a while, trying to get it to work right... I finally have it 95% sorted, just 2 things to complete.

1: Apply the bone system so I can move the main surface anywhere I like (not first time, shouldn't be hard)

2: Make the 4 sides of the pyramid (whose base is the main surface) only visible from inside. Which is proving to be a challenge.
So essentially, it needs to be that no matter what angle you stand viewing this pyramid, you can see its base and the farther sides, while the nearer ones are invisible. In *any* other application, I would just make the material 1-sided, no bother. In fact, most of the time, materials are 1-sided unless you specifically make them otherwise.
Can I find a way to do this in Daz? No. Also couldn't find anything about it in tutorials. Any help would be much appreciated. (Ideally, this would be to work in the Filament engine, but the material doesn't have to be Filament)

Richard Haseltine

I am not sure if this is applicable to Iray but in 3Delight I used the dot product of the normalised eye vector (the line from the camera to the point being looked at, adjusted to be one unit long) and the surface normal (the one-unit long line sticking out at right angles to the surface facing) - if it was negative the surface was facing the viewer, if positive it had its back to the viewer.