Full sample motion blur with cloth - cloth and collision object render issue. #21948

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Phil Leavens · 2010-04-08T04:50:15+02:00

Phil Leavens commented

2010-04-08 04:50:15 +02:00

%%%Cloth over an animated collision object "moves" during render using full sample motion blur. End result is cloth and object rendered overlapped.

Open blur_issue.blend
F12 render

Revision 28083
ArchLinux 32bit
AMD Phenom 3core
4 gigs ram
%%%

%%%Cloth over an animated collision object "moves" during render using full sample motion blur. End result is cloth and object rendered overlapped. 1. Open blur_issue.blend 2. F12 render Revision 28083 ArchLinux 32bit AMD Phenom 3core 4 gigs ram %%%

Phil Leavens commented

2010-04-08 04:50:15 +02:00

Changed status to: 'Open'

Matt Ebb commented

2010-06-27 07:57:07 +02:00

%%%Just an update here, the problem is that currently neither the cloth sim or point cache support subframes, as needed by motion blur. I've got it working with retrieving interpolated point cache results here (so this works properly after it's been baked) but it should really work for the sim itself as well...%%%

Matt Ebb commented

2010-07-16 03:40:27 +02:00

%%%Assigning to Daniel to check on for the sim code itself, is it possible to get the cloth sim itself to support floating point frames? It's possible to modify point cache to allow it.%%%

Magnus Løfgren commented

2010-09-03 12:27:38 +02:00

%%%This applies to all simulations using the cache system aswell, at least hair (Hair dynamics enabled), softbody and cloth.
Seems in a recent build that Hair Dynamics didn't even export vectors for vector blur, but I need to confirm that.%%%

%%%This applies to all simulations using the cache system aswell, at least hair (Hair dynamics enabled), softbody and cloth. Seems in a recent build that Hair Dynamics didn't even export vectors for vector blur, but I need to confirm that.%%%

Janne Karhu commented

2010-09-09 13:07:12 +02:00

%%%Partial fix committed, but setting as todo.

Pointcache can handle subframes, so fixed this (like Matt probably did too) by adding r.subframe to the cache reading.

This still only works when the cloth is baked or at least cached around the frame that's being rendered, but the problem is deeper than just converting cloth code to use float frames. If the cloth simulation would be calculated for each subframe as well the results could be different than running it just once per frame. So running the simulation in viewport would result in a different cloth shape than rendering an animation.

The proper solution could be to first step the whole scene to the next frame when rendering with subframes (so that simulations can be calculated and cached properly), but this kind of design change is really out of the scope of a simple bug fix and will have to be discussed later.%%%

%%%Partial fix committed, but setting as todo. Pointcache can handle subframes, so fixed this (like Matt probably did too) by adding r.subframe to the cache reading. This still only works when the cloth is baked or at least cached around the frame that's being rendered, but the problem is deeper than just converting cloth code to use float frames. If the cloth simulation would be calculated for each subframe as well the results could be different than running it just once per frame. So running the simulation in viewport would result in a different cloth shape than rendering an animation. The proper solution could be to first step the whole scene to the next frame when rendering with subframes (so that simulations can be calculated and cached properly), but this kind of design change is really out of the scope of a simple bug fix and will have to be discussed later.%%%

Janne Karhu commented

2010-09-09 13:07:12 +02:00

Changed status from 'Open' to: 'Archived'

Janne Karhu closed this issue

2010-09-09 13:07:12 +02:00

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Full sample motion blur with cloth - cloth and collision object render issue. #21948