Prevent/Hide Intersecting geometry from affecting refraction.

[richard_aubin]

I'm a jewelry designer, and having issues rendering gemstones that intersect with metal geometry.

The current solution I use is to cut away the intersecting geometry and leaving a small gap between the refracting model and the container/metal.

Is there anything within the settings of vray other materials that I can use to can help me avoid dong this extra labor / preparation work?

[konstantin_chaos]

Hi richard_aubin,

What you're currently doing is the best option. After all this is how things are in the real world.
With that in mind, I should mention that in V-Ray there is something called Clipper.
Using clippers you can basically perform render-time boolean operations.

What you need to do is duplicate the gemstone mesh and offset its surface so that it is a bit bigger than the original stone.
This will avoid overlapping geometry issues.

The material of this new geometry doesn't matter.

Convert the fatter peace into a Clipper by right-clicking on the V-Ray toolbar Clipper icon.
Make sure that only the metal peace you want to perform the boolean on is included in the Clipper affects:


As a result the ring is cut at render time:


Here's the difference with the gem visible:


Note that geometry with a different shape can also be used for clipping.
In simple scenarios like the one I tested with, this works great.
However, when you deal with more complex meshes some artefacts might start appearing (especially if the geometry being cut has overlapping surfaces).
That is why you should use this workflow with caution.

Regards,
Konstantin

[richard_aubin]

Thanks for the reply, I think this is what I might need as some of the boolean operation in rhino are failing due to bad geometry.. Will update after I try this out.

[richard_aubin]

Perfect. Works well with Grasshopper. Thank you very much for the explanation.

[konstantin_chaos]

Great to hear that this works for you.
And yes, it works in Grasshopper and is significantly easier to set up and control.