Jonas Sorgenfrei


About Me

Technical Director

FX TD / Pipeline | RISE Visual Effects Studios


Recent Forum Posts

Karma Refraction Black Faces on thin Material 2023年3月26日20:40

Hey @jsmack,

thank you so much for your responds. Yeah fair point, cranking the values up helped.
I was just testing up to refract 10, reflect 10 cause I wasn't considering that the light would bounce that much.

That's a good point, and makes totattly sense now.
Think in a production scene i would probably overwrite the limits just on the object with a geometry settings node then.

Thanks for the help!


Karma Refraction Black Faces on thin Material 2023年3月26日17:25


i'm struggeling getting a proper "thin" glass material working with Karma.
I tried to extrude a simple grid

and added a MaterialX Shader.

Ive added a simple Dome Light and enabled render Light Geometry for the test.

When rendering with Karma, it feels like there's kind of self shaddowing happening inside of the glass, which leads to the black sides.

When rendering the exact same setup with vray, it does the proper side refraction too:

Additionally when i increase the thickness of the extrusion to around 1, karma does proper refractions on the sides of my geo too.
Did i miss a specific setting or is this a bug in the renderer?

Karma True Displacment 2022年3月6日13:43

I'm looking for the Karma equivalent to the geometry toggle "Enable True Displacement" for mantra.
In mantra it was possible to toggle and disable it to only apply bumpmapping based on the displacement and not the whole displacement. (vm_truedisplace)
Is it possible to achieve the same thing with karma?