Particle Motion Blur very slow rendering #45019

New Issue

BernhardS · 2015-06-10T22:43:33+02:00

BernhardS commented

2015-06-10 22:43:33 +02:00

System Information
Windows 7 64bit, GTX 750ti

Blender Version
Broken: 2.74 000dfc0

Short description of error
Frames, in which particles are emitted, render extremely slow when motion blur is active (using cycles)

Long description
When rendering the animation on CPU, the frames 1-49 (in which new particles are generated) render very slow. (When using the GPU to render, the system will probably freeze completely.) From frame 50 on, it will render much faster.

Another user told me, that if he renders the same frame multiple times without changing any settings, it sometimes renders in a few seconds, and sometimes it takes minutes or does not render at all (I could not reproduce that). He also says, there does not seem to be a conjunction between the render-time and the state of particle emission, but I checked it twice and it is only slow until frame 49 on my system.
When he was trying to render with GPU (Quadro K4000) it crashed every time. He tested on 2.74 / 2.74.5 / 2.73a.

Exact steps for others to reproduce the error
Render the animation (with CPU to prevent the system from freezing), or render a frame between 1 and 49 and one >50.

ParticleBlurBug2.blend

**System Information** Windows 7 64bit, GTX 750ti **Blender Version** Broken: 2.74 000dfc0 **Short description of error** Frames, in which particles are emitted, render extremely slow when motion blur is active (using cycles) **Long description** When rendering the animation on CPU, the frames 1-49 (in which new particles are generated) render very slow. (When using the GPU to render, the system will probably freeze completely.) From frame 50 on, it will render much faster. Another user told me, that if he renders the same frame multiple times without changing any settings, it sometimes renders in a few seconds, and sometimes it takes minutes or does not render at all (I could not reproduce that). He also says, there does not seem to be a conjunction between the render-time and the state of particle emission, but I checked it twice and it is only slow until frame 49 on my system. When he was trying to render with GPU (Quadro K4000) it crashed every time. He tested on 2.74 / 2.74.5 / 2.73a. **Exact steps for others to reproduce the error** Render the animation (with CPU to prevent the system from freezing), or render a frame between 1 and 49 and one >50. [ParticleBlurBug2.blend](https://archive.blender.org/developer/F189173/ParticleBlurBug2.blend)

BernhardS commented

2015-06-10 22:43:33 +02:00

Changed status to: 'Open'

BernhardS commented

2015-06-10 22:43:33 +02:00

Added subscriber: @BernhardSteuer

Sergey Sharybin commented

2015-06-12 10:41:35 +02:00

Added subscriber: @Sergey

Sergey Sharybin commented

2015-06-12 10:41:36 +02:00

Actual problem seems to be caused by the way how particles are born? For some reason on lower frame numbers it is like half of the frame filled in with particles, which from quick look seems wrong. Would need to have a closer look tho.

blender-admin commented

2015-09-04 12:19:22 +02:00

This issue was referenced by 52fda9b0db

This issue was referenced by 52fda9b0dbdc561f905cd691532e361a0254113a

Sergey Sharybin commented

2015-09-04 12:22:31 +02:00

Changed status from 'Open' to: 'Resolved'

Sergey Sharybin closed this issue

2015-09-04 12:22:31 +02:00

blender-admin commented

2015-09-05 14:06:41 +02:00

This issue was referenced by blender/cycles@bb08fab201

This issue was referenced by blender/cycles@bb08fab201d6288a81c189200f8cec2c5b2adfe2

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Particle Motion Blur very slow rendering #45019