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Object should be invisible but receive cast shadows

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Grendizer
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Joined: 5月 2014
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Hi all
I'm trying to render cast shadows on a ground plane and I messed with the options in the object node's render tab, in "view visibility", but I couldn't find a way to cast shadows on this grid object while keeping it invisible.
This should work with Mantra and Karma.
Thanks for any tips.
DS
Houdini gamboler
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Kirill_Kolobushkin
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Joined: 8月 2021
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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
Edited by Kirill_Kolobushkin - 2025年8月29日 11:58:10

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Grendizer
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Hey thanks for your help. Could you tell me where to put these options? I didn't find them in the object node, light node or Mantra_ipr node... thanks!
Houdini gamboler
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Kirill_Kolobushkin
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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.

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