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Rigid body constraint object behaves strange if you run without Update Dependencies once
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--- Operating System, Graphics card ---
ubuntu 12.10, graphics unknown

--- Blender version with error ---
2.67b (2.67.0 r57123) from (thank you!)
(it uses rigid body tools, I believe that is available from version 2.66 and upwards only )

--- Short description of error ---
Rigid body constraint object, which is enabled by a driver on the first frame, behaves as not enabled if you forget to press 'Update Dependencies' right after pasting the function-definition-code in the console. Pressing Update dependencies afterwards might or might not work. Removing the Rigid body constraint's parent always works. After a while starting and stopping it might also work.

--- Steps for others to reproduce the error (preferably based on attached .blend file) ---
Open .blend file, any of the two attached ones. Move mouse over text panel,
Ctrl A to Select all
Ctrl C Copy
move mouse over Console panel
Ctrl V to paste and execute
DON'T Update Dependencies but move mouse on 3d panel and
Alt A to start animation, it will start without driver,
Esc to stop
NOW press Update Dependencies button in graph editor
Alt A in 3d panel, will propably start animation still without effective Hinge rigid body constraint object called loosefix.

If it is activated, the z-angle limit should stop the bouncing cube at 30 degrees more or less, see physics tab in properties if not visable. There you can see that it got enabled (checkbox), also in the log of the operating system console you can see that, but it doesn't act so.



Event Timeline

Ok I got a better bug report. I'm not sure if this is a cache problem, with removing the parent and such. Also by changing an active ring to passive and back again helps sometimes. I filed it as a new bug with a proper headline.

See 36104 Rigid-body-tool's constraint in animation doesn't listen to driver properly

Maybe this isn't needed any more.
Cheers, Freilauf

Hmm, so is this a duplicate of the other bug? I'm a little confused ;)

I think, yes. At least the other has similar-sounding effects (simulation not acting in accordance to driver) and is better reproduceable. Did you try them? Do you see the same result?

Cheers, freilauf

Sorry here too, 36104 Rigid-body-tool's constraint bug is not a bug, it's my own fault! About this bug here, I'm still not quite sure. As I mentioned, it can also be a cache problem. I've got another file, maybe easier to reproduce:
rigidbodyconstraint enable driver44.blend

#Just run the script, Alt-A in 3d panel, Esc in frame 50(+-)
#Update dependencies, Alt.A again
#cube jumps back at frame 50 suddenly instead of in frame 10+-

Maybe another error of me? I#ll have another look.
Cheers, freilauf

It may be a cache problem. I didn't find out more.


Hmm, I can't reproduce the problem, seems to work fine.

Julian Eisel (Severin) triaged this task as Needs Information from User priority.Mar 17 2015, 9:21 PM

@fr fff (freilauf), does the issue still occur in the Blender 2.74 RC?

No news since one week - and more than time to archive. ;)