Kirill Kolobushkin

In mantra you can build specific shader using shadowmatte node, depending of compose task bind it to AOV or render as beauty. unfortunately I don't imagine way to avoid beauty calculating.

In Karma use render geometry settings node to set shading properties, type LPE exp and it will be enough. This way is faster because beauty might not being rendering.

Hi!
you can use LPE: holdout;shadow;C.*<L.'domelight1'>
to make it works in Render Geometry Settings switch Holdout Mode to Matte or Background.

"C" avoids shadow reflections.
"<L.'..'>" split LPE tags
You can also make shadow casting geometry phantom

Hi! It seems that points need connection to all possible collision primitives before being scaled.

Try to build grid by connect adjacent pieces node and than give pscale. Also, in the Voronoi split, make sure to toggle the weight attribute.