Cycles Rendered view laggy while using particles #39341

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Gwenael Le Page · 2014-03-22T12:36:39+01:00

Gwenael Le Page commented

2014-03-22 12:36:39 +01:00

Hello,

Here is a link to a video showing the lags I am experiencing using Blender 2.70:
https://www.youtube.com/watch?v=AxM2gzGCGjg&feature=youtu.be
I recommend you watch the short video to get an idea of the problem before testing the file

I join the file here:
http://glp.lescigales.org/it/blender/Vase%20C%c3%a9ramique.blend

You'll find 3 layers: the bottom one has a vase and a plane, lamp etc.
Layer 2 has a mesh with an unapplied modifier stack and particles system on top of it.
Layer 1 has the same mesh and the modifier stack has been applied one by one from top to bottom, and there's still the particle system on top of that.

When entering cycles rendered view, everything is smooth with layer 1 turned on.
But if ytou switch to layer 2 and disable layer 1, you'll find the viewport to be 1. much slower to build (BVH thing and Copy to device, etc…) and 2. completely laggy. Impossible to pan and rotate fluidly.

With blender 2.69, it made no difference, both versions of the plant where equally fluid.

Hello, Here is a link to a video showing the lags I am experiencing using Blender 2.70: https://www.youtube.com/watch?v=AxM2gzGCGjg&feature=youtu.be I recommend you watch the short video to get an idea of the problem before testing the file I join the file here: http://glp.lescigales.org/it/blender/Vase%20C%c3%a9ramique.blend You'll find 3 layers: the bottom one has a vase and a plane, lamp etc. Layer 2 has a mesh with an unapplied modifier stack and particles system on top of it. Layer 1 has the same mesh and the modifier stack has been applied one by one from top to bottom, and there's still the particle system on top of that. When entering cycles rendered view, everything is smooth with layer 1 turned on. But if ytou switch to layer 2 and disable layer 1, you'll find the viewport to be 1. much slower to build (BVH thing and Copy to device, etc…) and 2. completely laggy. Impossible to pan and rotate fluidly. With blender 2.69, it made no difference, both versions of the plant where equally fluid.

Gwenael Le Page commented

2014-03-22 12:36:39 +01:00

Changed status to: 'Open'

Gwenael Le Page commented

2014-03-22 12:36:39 +01:00

Added subscriber: @gwentiv

Thomas Dinges commented

2014-03-23 12:54:10 +01:00

Added subscriber: @ThomasDinges

Thomas Dinges commented

2014-03-23 12:54:10 +01:00

Confirmed in the Viewport with Blender 2.70.

Thomas Dinges commented

2014-03-23 13:01:33 +01:00

Weird thing: On Windows it renders but is slower. On Linux and Mac OS it does not go beyond Sample 1, it constantly refreshes.

Lukas Tönne self-assigned this 2014-03-23 13:56:20 +01:00

Gwenael Le Page commented

2014-03-23 15:42:04 +01:00

Hi Lukas and Thomas.

First of all , a big thank you for having a look at that, much appreciated.

A detail that may have its importance (at least intuitively I'd say it may have…) is that in the particle system, I chosed to tick the "use modifier stack" option of the "emission" subpanel. As the behaviour is different when the stack is applied or not, I thought that may be of importance.

I will try to reproduce the error on another file and single our if that particular option is relevant in that case.

EDIT: no success. The test file I've made showed no particuliar impact from that specific toggle.

Hi Lukas and Thomas. First of all , a big thank you for having a look at that, much appreciated. A detail that may have its importance (at least intuitively I'd say it may have…) is that in the particle system, I chosed to tick the "use modifier stack" option of the "emission" subpanel. As the behaviour is different when the stack is applied or not, I thought that may be of importance. I will try to reproduce the error on another file and single our if that particular option is relevant in that case. EDIT: no success. The test file I've made showed no particuliar impact from that specific toggle.

Lukas Tönne was unassigned by Sergey Sharybin

2014-03-23 16:53:16 +01:00

Sergey Sharybin self-assigned this 2014-03-23 16:53:16 +01:00

Sergey Sharybin commented

2014-03-23 16:53:16 +01:00

Added subscriber: @LukasTonne

Lukas Tönne commented

2014-03-24 10:36:01 +01:00

This is broken since the threaded despgraph update (709041ed0b)

Seems to be caused by crappy particle check in the modifier:
https:developer.blender.org/diffusion/B/browse/master/source/blender/modifiers/intern/MOD_particlesystem.c;f8c247f21b8e489750e3847a4a2270c1146cbbc2$182Somehowwhen the modifier stack was evaluated in 2.69 it would (imo correctly) use the viewport settings instead of render settings for the modifier stack. I'm actually not sure how this worked, since what Cycles does suggests it wouldalways// use the render settings!
https://developer.blender.org/diffusion/B/browse/master/intern/cycles/blender/blender_object.cpp;f8c247f21b8e489750e3847a4a2270c1146cbbc2$449
(1==eModifierMode_Realtime, 2==eModifierMode_Render)

This is the same code in 2.69 and master, not sure what prevented modifiers from using "realtime" settings before.

Further there is some kind of randomness in the skin modifier! For some reason it always generates slightly different vertex/face counts each time it is evaluated. This might be the reason the particle system subsequently updates over and over, because it detects a modified input mesh and re-distributes particles.

This is broken since the threaded despgraph update (709041ed0b) Seems to be caused by crappy particle check in the modifier: https:*developer.blender.org/diffusion/B/browse/master/source/blender/modifiers/intern/MOD_particlesystem.c;f8c247f21b8e489750e3847a4a2270c1146cbbc2$182*Somehow*when the modifier stack was evaluated in 2.69 it would (imo correctly) use the viewport settings instead of render settings for the modifier stack. I'm actually not sure how this worked, since what Cycles does suggests it would*always// use the render settings! https://developer.blender.org/diffusion/B/browse/master/intern/cycles/blender/blender_object.cpp;f8c247f21b8e489750e3847a4a2270c1146cbbc2$449 (1==eModifierMode_Realtime, 2==eModifierMode_Render) This is the same code in 2.69 and master, not sure what prevented modifiers from using "realtime" settings before. Further there is some kind of randomness in the **skin modifier**! For some reason it always generates slightly different vertex/face counts each time it is evaluated. This might be the reason the particle system subsequently updates over and over, because it detects a modified input mesh and re-distributes particles.

blender-admin commented

2014-03-24 13:10:58 +01:00

This issue was referenced by blender/blender-addons-contrib@83f2012300

This issue was referenced by blender/blender-addons-contrib@83f2012300acadafd359307e7a00bd71e67e3fd7

blender-admin commented

2014-03-24 13:10:58 +01:00

This issue was referenced by 83f2012300

This issue was referenced by 83f2012300acadafd359307e7a00bd71e67e3fd7

Lukas Tönne commented

2014-03-24 13:16:42 +01:00

Changed status from 'Open' to: 'Resolved'

Lukas Tönne closed this issue