Blender Foundation: Blender 2.x BF release: Detail: 25206 Particles system can't start at frame 0

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[#25206] Particles system can't start at frame 0

Date:
2010-12-13 18:39 Priority:
3

State:
Closed

Submitted by:
Stephane SOPPERA (soppera) Assigned to:
Janne Karhu (jhk)

Category:
Tools Status:
Fixed / Closed

Relates to: Duplicates:

Patches:

Summary:
Particles system can't start at frame 0

Detailed description

Hi,

In Blender 2.55.0 (r32738, the official win32 build) the simulation of a particles system does not start at frame 0 even if the Emission > Start value has been set to frame 0.

Let's take for example the "particle start.blend" file attached to this bug report. If you bake the particles, with a system having Emission > Start and Emission > End both set to 0, then you won't see any particle on frame 0. You will only see them on frame 1 (and sub-sequent frames).

Note that changing the Start and End and putting a value >= 1 works as expected: the particles are correctly emitted at the chosen frame.
There seems to be a bug only for frame 0.

It may be due to the fact that on previous version of blender (on 2.49 for example), the start frame of a scene was always >=1. It seems that the particle system is assuming this is still true.

Regards,
Stéphane

Followup

Message

Date: 2010-12-13 18:48
Sender: Ton Roosendaal
The attachment didn't come through, can you retry?

I tried default cube, emission->start/end both on zero, particles show fine before and after bake. In current svn and in 2.55 release.

Date: 2010-12-13 18:51
Sender: Stephane SOPPERA
Hi,

I failed to attach the data; there is a

Date: 2010-12-13 18:52
Sender: Stephane SOPPERA
Oups, sorry for the last partial comment.

This time, the attachement succeeded but it also kept my partial failure message ;-)

I'll test with the simple cube.

Regards,
Stéphane

Date: 2010-12-13 18:55
Sender: Stephane SOPPERA
I have tested with the default cube, and I have the same issue: the particles are not visibile when the current frame is frame 0.

Stéphane

Date: 2010-12-13 19:15
Sender: Stephane SOPPERA
To make things clearer I've created a video of the issue with a simple cube:
http://www.youtube.com/watch?v=kk5FFpPnvkY

(I've put it on youtube since the file size is 5Mo).

In the video, I first try with setting start and end at frame 0. You can see after the bake that the particles are not visible at frame 0 (see the timeline at the bottom of the screen) but only visible at frame 1 (and upper).

The I change start and end to frame 2. After bake you can see that particles are visible on frame 2 (and upper), as expected.

Do you reproduce this issue?

Stéphane

Date: 2010-12-13 19:21
Sender: Ton Roosendaal
Ahh, i forgot to move the scene frame to zero. :) That's why .blend files are always so useful :)
Will leave it to Janne now. Thanks!

Date: 2010-12-14 16:49
Sender: Janne Karhu
Fix committed, thanks for the report!

Attached Files:

Name	Date	Download

particle start1.blend	2010-12-13 18:51	Download

Changes:

Field	Old Value	Date	By

status_id	Open	2010-12-14 16:49	jhk
close_date	None	2010-12-14 16:49	jhk
Status	Investigate	2010-12-14 16:49	jhk
File Added	14078: particle start1.blend	2010-12-13 18:51	soppera
assigned_to	none	2010-12-13 18:48	ton
Status	New	2010-12-13 18:48	ton