noicevstime
Feb. 3, 2026 02:22:49
Hi all,
In H20.5 and H21 karma, is there a way to control the number of CPU/XPU threads used during viewport rendering and live rendering (the live render node in H21). Not talking about Local clones.
I would love to save some threads for UI, remote deskstop, and other stuff.
The info I can find is for USD_render_ROP that has to do with render to disk. Or it's setting on the OS level that is trying to limit the total threads used by Houdini. Neither is ideal.
Cheers.
robp_sidefx
Feb. 3, 2026 08:32:57
We don't currently expose a dedicated control for reserving threads in Live Renders, but do have an open RFE to add this.
Ben Toogood Aardman
Feb. 3, 2026 11:59:20
As a work around, I've found you can explicitly set the reserve threads count if you dive into the liverender 'USER_AREA' and use a wrangle to modify your rendersettings prim
i@karma:global:ipr_reserve_threads = 2;
noicevstime
Feb. 3, 2026 21:21:29
robp_sidefx
We don't currently expose a dedicated control for reserving threads in Live Renders, but do have an open RFE to add this.
Thanks for the update, Rob. Looking forward to seeing a features like this added. I am hoping it will work with both live render and viewport rendering.
cheers.
noicevstime
Feb. 3, 2026 21:48:54
Ben Toogood Aardman
As a work around, I've found you can explicitly set the reserve threads count if you dive into the liverender 'USER_AREA' and use a wrangle to modify your rendersettings prim
i@karma:global:ipr_reserve_threads = 2;
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Thanks so much Much, Ben. I'll give this a go.