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Description

Physics simulation systems including rigid bodies, cloth, softbodies, smoke fluids and particles.

Developers

Bullet: @Erwin Coumans (erwin)
Rigid Body: @Sergej Reich (sergof)
Cloth: @Daniel Genrich (genscher)
Smoke: @Miika Hamalainen (miikah) @Daniel Genrich (genscher)
Fluids: @Daniel Genrich (genscher) @Nils Thuerey (n_t)
Particles: @Janne Karhu (jhk) @Lukas Toenne (lukastoenne)
Softbody: @Jens Ole Wund(bjornmose) (bjornmose)

Recent Activity

Thu, Jun 6

Brecht Van Lommel (brecht) merged T65541: Hair particles don't follow rigid body in animation into T58044: Issue with adding hair to rigid body.
Thu, Jun 6, 2:19 PM · BF Blender: 2.8, Physics

Sat, Jun 1

Rombout Versluijs (rombout) added a comment to T53083: Bake All Dynamics doesn't work when baking particle hair.

I also run into this issue today. Tried everything within my knowledge but it wont work. SIngle bake does work , but thats not useful with multiple items. How did they do the open movie projects without this?!?!?

Sat, Jun 1, 6:37 AM · Physics, BF Blender

Wed, May 29

Brecht Van Lommel (brecht) closed T56145: Blender is not renderng mesh with cloth phisics as Archived.

This is indeed a known limitation, we should improve the UI here once but for now it is require to have the same level for both.

Wed, May 29, 4:32 AM · Physics, Rendering, BF Blender

Tue, May 21

Sebastián Barschkis (sebbas) closed T58492: smoke flow jitters around flow source when using adaptive domain as Resolved by committing rB1036ae2acdea: Fix T58492: Removes jitter when using adaptive smoke domains.
Tue, May 21, 10:24 PM · BF Blender, Physics
alex anguix (alexang) added a comment to T64879: Setting RigidBodyCollection to a new Collection sets all children to Dynamic/Active.

That should work fine, yes.

Tue, May 21, 12:28 PM · Physics, BF Blender
Philipp Oeser (lichtwerk) added a comment to T64879: Setting RigidBodyCollection to a new Collection sets all children to Dynamic/Active.

Still not sure if I understand correctly:

Tue, May 21, 12:08 PM · Physics, BF Blender
alex anguix (alexang) added a comment to T64879: Setting RigidBodyCollection to a new Collection sets all children to Dynamic/Active.

Have a decent play with the removing and adding, cause it produces different results all the time.

Tue, May 21, 11:48 AM · Physics, BF Blender
Philipp Oeser (lichtwerk) added a comment to T64879: Setting RigidBodyCollection to a new Collection sets all children to Dynamic/Active.

Problem is Removing the Ridgid Body World in the first place [which in turn removes the ridgid bodies from the objects].
If you want to keep the ridgid body settings (but for some reason wont those object not to participate in the simulation), why not move the objects to a different collection [not the RidgidBodyWorld one]?

Tue, May 21, 11:30 AM · Physics, BF Blender
alex anguix (alexang) added a comment to T64879: Setting RigidBodyCollection to a new Collection sets all children to Dynamic/Active.

The big issue here though is that it sets EVERYTHING to default Dynamic/Active and resets mass. Even if it already had a rigidbody. So you lose everything you set up already.

Tue, May 21, 11:17 AM · Physics, BF Blender

May 20 2019

alex anguix (alexang) added a comment to T64877: Adding and Removing RigidBodyWorld is broken.

I'm not sure if this belongs to https://developer.blender.org/T64879 or here,

May 20 2019, 2:51 PM · Physics, BF Blender
Philipp Oeser (lichtwerk) closed T64879: Setting RigidBodyCollection to a new Collection sets all children to Dynamic/Active as Invalid.

As stated in T64877, this is true for all (EDIT: not all, some) Physics types and these are not just disabled, but removed.

May 20 2019, 2:22 PM · Physics, BF Blender
Philipp Oeser (lichtwerk) triaged T64877: Adding and Removing RigidBodyWorld is broken as Confirmed, Medium priority.

Indeed, seems weird.

May 20 2019, 2:11 PM · Physics, BF Blender
Bastien Montagne (mont29) reassigned T58492: smoke flow jitters around flow source when using adaptive domain from Bastien Montagne (mont29) to Sebastián Barschkis (sebbas).
May 20 2019, 1:23 PM · BF Blender, Physics
Sebastián Barschkis (sebbas) reopened T58492: smoke flow jitters around flow source when using adaptive domain as "Open".

Think this bug is back - bb88485a1693751baff8a61917987323dbee654a distorts smoke with the adaptive domain.

May 20 2019, 11:39 AM · BF Blender, Physics

May 18 2019

zebus3d (ofuscado) added a comment to T51111: Using an added Cube in combination with Particles > Volume > Grid results in missing particles..

This continues to happen in the new blender 2.80 3b8ae2c08f5c
When you create a cube and fill it with particles in volume mode and with grid distribution, a diagonal row is missing, if you invert the grid only this row appears.

May 18 2019, 4:46 PM · Physics, BF Blender

May 14 2019

Marco (nacioss) added a comment to T57343: Blender 2.80 does not correctly handle the physical collision data generated by version 2.79.

It is working in 2.8 build of 2019-05-13

May 14 2019, 12:37 PM · Physics, BF Blender

May 5 2019

Nils Thuerey (n_t) added a comment to T59995: Mantaflow Review.

@Bastien Montagne (mont29) thanks for the detailed comments! We'll have to more carefully look at the points you mentioned. Good idea to make the naming scheme consistent, to properly indicate the parts of the new solver. I'd suggest using "manta" there to distinguish it from the old smoke and liquid version.

May 5 2019, 3:44 PM · Physics, BF Blender

May 4 2019

Bastien Montagne (mont29) added a comment to T59995: Mantaflow Review.

Note: just updated the branch against latest master (was kinda painful, thanks to some 'cleanup' in BKE physics files :( ), would be nice if patches could be updated too.

May 4 2019, 3:57 PM · Physics, BF Blender
Bastien Montagne (mont29) added a comment to T59995: Mantaflow Review.

Some initial usability review after using the branch for a few tests, and a first quick review of the patches:

May 4 2019, 11:10 AM · Physics, BF Blender

May 2 2019

Bastien Montagne (mont29) added a comment to T59995: Mantaflow Review.

@Nils Thuerey (n_t) Hmm, looks like the branch could use a merge with master again. ;)

May 2 2019, 4:32 PM · Physics, BF Blender
Nils Thuerey (n_t) added a comment to T59995: Mantaflow Review.

@Brecht Van Lommel (brecht), @Bastien Montagne (mont29) - okay, very good!

May 2 2019, 1:56 PM · Physics, BF Blender

May 1 2019

Bastien Montagne (mont29) added a comment to T59995: Mantaflow Review.

Yes, it’s still on my radar for this week or next one…

May 1 2019, 3:54 PM · Physics, BF Blender
Brecht Van Lommel (brecht) added a comment to T59995: Mantaflow Review.

The plan is still for @Bastien Montagne (mont29) to do the initial code review. @Bastien Montagne (mont29), will you have time to do this in the next few weeks? Spending like one day to go over the code and testing the functionality.

May 1 2019, 11:25 AM · Physics, BF Blender

Apr 26 2019

Nils Thuerey (n_t) added a comment to T59995: Mantaflow Review.

I have another question here for the experienced blender devs (@Brecht Van Lommel (brecht) @Sam Van Hulle (sam_vh) @Martin Felke (scorpion81) @Jacques Lucke (JacquesLucke) and maybe others?): what would be the best next steps for an official 'approval' of the mantaflow diffs? I saw the 2.8 timeline, and I guess it would be ideal to verify that the patch is in a good enough state some time soon. Then it could be merged into the main branch as soon as possible after 2.8 is released in July, such that it can be included for the 2.81 release.

Apr 26 2019, 12:41 PM · Physics, BF Blender

Apr 25 2019

Sergey Sharybin (sergey) merged T63761: hair particles not updated if the parent is an active rigid body object into T58044: Issue with adding hair to rigid body.
Apr 25 2019, 12:41 PM · BF Blender: 2.8, Physics

Apr 23 2019

Nils Thuerey (n_t) added a comment to T59995: Mantaflow Review.

@Brecht Van Lommel (brecht) Okay, yes - the GIL seems to be unproblematic so far. It could make the UI somewhat unresponsive when baking large sims, though. The new node system notes look interesting. I think for mantaflow it would neat to go for the "everything-nodes" direction, where a node graph would define the data flow of the simulation. This could then use a python back-end, or directly hook into the mantaflow functions (the functions that are exposes to python are the crucial ones that ideally would also be available as nodes). It's definitely a good point to keep in mind.

Apr 23 2019, 1:53 PM · Physics, BF Blender

Apr 18 2019

Brecht Van Lommel (brecht) added a comment to T59995: Mantaflow Review.

Ok. The main concern is not so much that it's slow for fluid simulation by itself, but if multiple performance sensitive areas use Python it does become a problem to have these global locks. If this is how the Mantaflow API works and it's a big burden to use C++ instead it seems acceptable.

Apr 18 2019, 5:00 PM · Physics, BF Blender
Nils Thuerey (n_t) added a comment to T59995: Mantaflow Review.

@Brecht Van Lommel (brecht) Good question, to add to sebbas comments, there are a few reasons for the python bindings: a first mundane one is that that's how the mantaflow solver worked originally, and it would have been a lot more work to switch to C/C++ bindings. Also, the performance impact is negligible, as mantaflow provides all the solver building blocks via python, but each of the steps is quite expensive. So there are no low-level operations in python (e.g. access to grid cells), but just a small number of calls to high level functions that typically make several passes over the full grid.

Apr 18 2019, 4:19 PM · Physics, BF Blender
joel heethaar (joel_nl) updated subscribers of T59995: Mantaflow Review.

There's a pull request from David Ullmann extending the NOPYTHON option.

Apr 18 2019, 11:16 AM · Physics, BF Blender
Sebastián Barschkis (sebbas) added a comment to T59995: Mantaflow Review.

@Brecht Van Lommel (brecht) Right now the only way to access all Mantaflow functions is through Python. In terms of performance I wouldn't say that this is an issue. Once the Manta solver acquires the GIL it will compute one "step" and only once completed release it. The time between steps where other resources (like the UI) can acquire the GIL and Manta has to wait for it would be the only delay during a bake job. This delay is negligible from my experience unless there are other resources that could block the GIL for a very long time.

Apr 18 2019, 9:57 AM · Physics, BF Blender
Sebastián Barschkis (sebbas) added a comment to T59995: Mantaflow Review.

@Nils Thuerey (n_t) Yes, you're right. Those lines won't be needed in the future anymore. Will remove them.

Apr 18 2019, 9:19 AM · Physics, BF Blender

Apr 17 2019

Brecht Van Lommel (brecht) added a comment to T59995: Mantaflow Review.

Can someone remind me why this is integrated through Python rather than C++, and how much work it would to change it to C++?

Apr 17 2019, 11:37 AM · Physics, BF Blender
Nils Thuerey (n_t) added a comment to T59995: Mantaflow Review.

@Sebastián Barschkis (sebbas) - I noticed the exported python scene has a few lines at the top for OS/multi-processing checks that don't seem to be used or necessary. (from "withMP ... up to VARIABLES", ca. lines 8 to 18). Those could be removed, right?

Apr 17 2019, 9:46 AM · Physics, BF Blender

Apr 16 2019

Brecht Van Lommel (brecht) added a comment to T63606: Soft Body bake doesn't delete in "Disk Cache" mode.

@Ulysse Martin (youle), thanks for the video. What I tested is that when I'm at e.g. frame 50 and press Delete Bake then, I would expect it to remove all results from the physics sim, and you'd have to go back to frame 1 and play to simulate again. That doesn't happen here. If you're at frame 1 this patch works fine indeed.

Apr 16 2019, 4:43 PM · Physics, BF Blender
Ulysse Martin (youle) added a comment to T63606: Soft Body bake doesn't delete in "Disk Cache" mode.

I join a .gif video to show before and after applying the patch on my computer:

Apr 16 2019, 4:35 PM · Physics, BF Blender
Brecht Van Lommel (brecht) added a comment to T63606: Soft Body bake doesn't delete in "Disk Cache" mode.

This patch doesn't seem to do anything for me.

Apr 16 2019, 4:00 PM · Physics, BF Blender
Sebastian Parborg (zeddb) assigned T63606: Soft Body bake doesn't delete in "Disk Cache" mode to Sergey Sharybin (sergey).
Apr 16 2019, 11:41 AM · Physics, BF Blender

Apr 15 2019

Ulysse Martin (youle) added a comment to T63606: Soft Body bake doesn't delete in "Disk Cache" mode.

I can confirm an issue with delete bake action.

Apr 15 2019, 12:07 AM · Physics, BF Blender

Apr 14 2019

Casey (BagelCo) added a project to T63606: Soft Body bake doesn't delete in "Disk Cache" mode: Physics.
Apr 14 2019, 10:50 PM · Physics, BF Blender
Emmanuel A. Briones (eabriones) removed a watcher for Physics: Emmanuel A. Briones (eabriones).
Apr 14 2019, 6:55 AM
Emmanuel A. Briones (eabriones) added a watcher for Physics: Emmanuel A. Briones (eabriones).
Apr 14 2019, 6:55 AM

Apr 8 2019

Nils Thuerey (n_t) added a comment to T59995: Mantaflow Review.

Hi everyone, great to see the manta integration being re-revived! @Sebastián Barschkis (sebbas) thanks for the large patch collection. I just checked out and tried the revised diff "from scratch". Works nicely on my MAC. The sims also run through without problem (I tested based on the quick-smoke and quick-liquid setups). So I think this patch looks good, overall. There are some obvious next steps, like removing the old liquid/smoke modifiers, and cleaning up the code, but I think this would be better to address once the manta code is integrated.

Apr 8 2019, 10:09 AM · Physics, BF Blender

Apr 7 2019

Sebastián Barschkis (sebbas) added a comment to T59995: Mantaflow Review.

@Bastien Montagne (mont29) Yes, that's definitely a good idea. I just updated the diffs (now it's branched from the 2.8 "master") and also synced it with the fluid-mantaflow branch which can be used for test builds. From here we could now get the review rolling.

Apr 7 2019, 7:42 PM · Physics, BF Blender

Apr 4 2019

Benjamin Meyer (Anvilarion) added inline comments to D4591: Correctly display number of cached frames during simulation with negative start frame.
Apr 4 2019, 6:48 PM · BF Blender: Staging, Physics
Sergey Sharybin (sergey) closed D4636: Fix: Erratic collision response when using constraints on colliders.
Apr 4 2019, 11:06 AM · Physics
Sergey Sharybin (sergey) added inline comments to D4591: Correctly display number of cached frames during simulation with negative start frame.
Apr 4 2019, 10:20 AM · BF Blender: Staging, Physics
Mal Duffin (mal_cando) added a comment to T58044: Issue with adding hair to rigid body.

Hi Sergey,

Apr 4 2019, 9:41 AM · BF Blender: 2.8, Physics
Sergey Sharybin (sergey) claimed T58044: Issue with adding hair to rigid body.

Would need to have a closer look, but could be caused by the change in the evaluation order of rigid body, similar to T63028.

Apr 4 2019, 9:36 AM · BF Blender: 2.8, Physics

Apr 3 2019

Brecht Van Lommel (brecht) edited reviewers for D4636: Fix: Erratic collision response when using constraints on colliders, added: Sergey Sharybin (sergey); removed: Physics.
Apr 3 2019, 7:14 PM · Physics
Brecht Van Lommel (brecht) edited reviewers for D4591: Correctly display number of cached frames during simulation with negative start frame, added: Sergey Sharybin (sergey); removed: Sergej Reich (sergof).
Apr 3 2019, 7:13 PM · BF Blender: Staging, Physics