Long time render Hair Particles #86632

New Issue

Gérald · 2021-03-16T15:54:38+01:00

Gérald commented

2021-03-16 15:54:38 +01:00

System Information
Operating system: Windows-10-10.0.19041-SP0 64 Bits
Graphics card: GeForce GTX 1060 6GB/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 388.43

Blender Version
Broken: version: 2.92.0, branch: master, commit date: 2021-02-24 16:25, hash: 02948a2cab
Worked: 2.83
Caused by switching to Embree for hair 207338bb58, 99436acde8

Hello,

When I open an old blender file (v2.83) containing a plan with hair particles (grass), with blender 2.92 ...
When rendering with CPU, the rendering time is multiplied by 4 !!!

Test Blend file :
Test Hair v1.blend

Rendering on blender 2.83 -> 4.30 min

Rendering on blender 2.92 -> 19.52 min

I have the impression that the quality of the blades of grass and more detail, however I did not change any parameter!

Is it normal that the rendering time is so long on blender 2.92?

cordially

**System Information** Operating system: Windows-10-10.0.19041-SP0 64 Bits Graphics card: GeForce GTX 1060 6GB/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 388.43 **Blender Version** Broken: version: 2.92.0, branch: master, commit date: 2021-02-24 16:25, hash: `02948a2cab` Worked: 2.83 Caused by switching to Embree for hair 207338bb58, 99436acde8 Hello, When I open an old blender file (v2.83) containing a plan with hair particles (grass), with blender 2.92 ... When rendering with CPU, the rendering time is multiplied by 4 !!! Test Blend file : [Test Hair v1.blend](https://archive.blender.org/developer/F9894972/Test_Hair_v1.blend) Rendering on blender 2.83 -> 4.30 min ![Test Hair CPU 2.83.jpg](https://archive.blender.org/developer/F9894969/Test_Hair_CPU_2.83.jpg) Rendering on blender 2.92 -> 19.52 min ![Test Hair CPU 2.92.jpg](https://archive.blender.org/developer/F9894970/Test_Hair_CPU_2.92.jpg) I have the impression that the quality of the blades of grass and more detail, however I did not change any parameter! Is it normal that the rendering time is so long on blender 2.92? cordially

Gérald commented

2021-03-16 15:54:38 +01:00

Added subscriber: @Baboo13400

Philipp Oeser commented

2021-03-16 18:27:43 +01:00

Added subscriber: @lichtwerk

Philipp Oeser commented

2021-03-16 18:27:43 +01:00

Changed status from 'Needs Triage' to: 'Needs Developer To Reproduce'

Philipp Oeser commented

2021-03-16 18:27:43 +01:00

Since switching to Embree for hair 207338bb58, 99436acde8 this is using a different method for hair intersections.

It looks like the performance impact was somewhat expected, from the commit message:

Peformance and quality primitives is quite different than before

The main problem here is performance. For CPU and OpenCL rendering performance
seems usually quite close or better for similar quality results.

However for CUDA and Optix, performance of 3D curve intersection is problematic,
with e.g. 1.45x longer render time

This particular scene can be tweaked a bit further (e.g. setting the Rounded Ribbons Curve Subdivisions to zero still gives you better primitives than what the original file had in 2.83), but it is still considerably slower now (compared to 2.83).

This might all be a thing we have to live with (switch to embree also brought huge benefits in terms of memory consumption and motionblur performance iirc), but I would still like the rendering department to have a final look (and decision) on this.

Since switching to Embree for hair 207338bb58, 99436acde8 this is using a different method for hair intersections. It looks like the performance impact was somewhat expected, from the commit message: > Peformance and quality primitives is quite different than before > The main problem here is performance. For CPU and OpenCL rendering performance > seems usually quite close or better for similar quality results. > However for CUDA and Optix, performance of 3D curve intersection is problematic, > with e.g. 1.45x longer render time This particular scene can be tweaked a bit further (e.g. setting the Rounded Ribbons Curve Subdivisions to zero still gives you better primitives than what the original file had in 2.83), but it is still considerably slower now (compared to 2.83). This might all be a thing we have to live with (switch to embree also brought huge benefits in terms of memory consumption and motionblur performance iirc), but I would still like the rendering department to have a final look (and decision) on this.

Evan Wilson commented

2021-03-16 22:09:11 +01:00

Added subscriber: @EAW

Evan Wilson commented

2021-03-16 22:09:11 +01:00

There have been updates to curves in Embree’s change log for versions 3.11 & 3.12, but I don’t know if they would help reduce render times. Blender currently uses version 3.10.
https://github.com/embree/embree/blob/master/CHANGELOG.md

There have been updates to curves in Embree’s change log for versions 3.11 & 3.12, but I don’t know if they would help reduce render times. Blender currently uses version 3.10. https://github.com/embree/embree/blob/master/CHANGELOG.md

gabe2252 commented

2021-03-17 02:45:59 +01:00

Added subscriber: @gabe2252

Pratik Borhade changed title from ~~Long time render Hair Particules - Blender 2.92~~ to Long time render Hair Particles

2021-07-20 13:47:02 +02:00

Pratik Borhade commented

2021-07-20 13:49:01 +02:00

Added subscriber: @PratikPB2123

Pratik Borhade commented

2021-07-20 13:49:01 +02:00

Can confirm the difference in rendering time between 2.83 and 2.93LTS.

Philipp Oeser removed the

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Long time render Hair Particles #86632