Is it possible to disable shadows in cycles for vertex groups on a mesh? Like some parts don’t cast shadow while others do?
You can disable shading for vertex groups using vertex colors:
Those white diamonds are areas that should be fully shaded, but because I painted those vertices black (giving 0 to the Mix Shader), they instead are fully emissive (non-shaded). Is that what you are looking for?
1 Like
Not exactly. I wanted to disable cast shadows from a vertex group within a mesh. Also does the method you just showed work in cycles? Thanks
Here, I have a Plane, a Torus and a Light.
.
.
Most of the Torus casts a shadow, part does not. That part has a seperate (but equal) material which has it’s Shadow mode set to “None”.
Like that?
3 Likes
You can’t use vertex groups in shader editor directly. So use vertex colours instead. Also this is all is probably cycles only.
Example with disabling shadows but whole object still being visible for camera using vertex colors:
Parts of mesh painted with black vertex colour don’t cast shadow (they are transparent for rays) but are still visible for camera. Still, I would recommend @calpgrmr method unless you really need smooth gradient transitions between parts which cast and don’t cast shadows.
Now about that “can’t use vertex groups in shader editor directly” bit - it’s possible with geometry nodes but not recommended because of very overcomplicated setup:
You need to define vertex weight name, vertex color name, add geonodes, transfer attributes from weights to colors, add inputs / outputs in modifier… I might have forgot to describe some step but it’s in the picture.
3 Likes
Yes just this. But I think this method wouldn’t be possible in cycles, right?
Try it 
(I’m 99.9% sure it would work in cycles, you just have to have two materials on one object)
But cycles doesn’t have shadow mode settings for objects.
In that case, you could try Format64’s suggestion, which is Cycles only
1 Like
Thanks for your help
1 Like
Cycles shadow settings are in object properties tab:
And in eve they are are in material properties tab:
2 Likes
Yes but since I wanted to disable cast shadow partially on a single mesh(in cycles), disabling shadow ray would completely disable the whole mesh’s shadow.
I tried out the vertex color method and it works well for me. Thanks a lot for helping 