I try to make a rug generator with geometry nodes. I already have a functional generator for the shape of the rug but I struggle to render a large amount of hairs.

I might need to make large rugs (like 9' x 12').

I actually have a "Generate Hair Curves" node with 100 as density and a "Interpolate Hair Curves" with 16000 as density. I still have visible holes between each hair and I struggle to render large rugs despite my RTX 4070 and my 32Gb of RAM.

blender render of a hair system

Please, do you have any performance and optimizations tips ? I'm used to particles systems, not to geometry nodes hairs.

Edit : I am able to render a lot more hairs than this with a particle system, with a lot of children. It seems Geometry Nodes just doesn't interpolate children in the same way.

But I need to use Geometry Nodes cause my geometry is actually from it so having a particle modifier above it doesn't work.

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    $\begingroup$ There are two BVH calculation methods. One optimizes for speed of hair rendering at the cost of higher ram usage. You might need to disable this and suffer the slower speed. $\endgroup$ Jan 17 at 15:39
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    $\begingroup$ What means "struggle to render"? Too long render times? Bad results? Too much VRAM usage? Crash? $\endgroup$
    – Blunder
    Jan 17 at 15:46
  • $\begingroup$ Blender just crash and my PC follow.. Yes I tried to disable BVH. For the moment I'm able to render correctly by passing some information from geometry nodes to the particles system. So technically, my problem is solved. But it still frustrating to use both systems while Geometry Nodes can do it by itself. I don't know why there is such a performance gap between Geometry Nodes and Particle Systems. Here's the render (low samples) : imgur.com/AjjAVmu $\endgroup$ Jan 17 at 16:38
  • $\begingroup$ Have you checked how many hair curves are generated by the GN? $\endgroup$
    – Blunder
    Jan 18 at 2:07
  • $\begingroup$ How can I check how many hair curves are generated by the GN ? GN is geometry nodes ? $\endgroup$ Jan 23 at 11:58


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