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box box collision #351

Closed GoogleCodeExporter closed 9 years ago

GoogleCodeExporter commented 9 years ago 
What steps will reproduce the problem?
1. Having two boxes (cube with rigid body box), each with size x:10, y:2,
z:0.75
2. Position of box1: x:0, y:0, z:5, rotx: 0, roty: 0, rotz: 0
3. Position of box2: x:0.5, y:0, z:15, rotx: 90, roty: 0, rotz: 0

What is the expected output? What do you see instead?
Both should collide and rotation might happen on x-axis and y-axis. But
rotation happens on z-axis (totally unrealistic) and for a very high amount
of 180 degree.

Note that this bug does not occur when changing x-position of box2 to 0. So
this behaviour only takes place with special collision areas.

I've attached a sequence of 4 images where you can see the strange rotation
happening.

What version of the product are you using? On what operating system?
MacOS

Original issue reported on code.google.com by jont...@googlemail.com on 2 Mar 2010 at 3:20

Attachments:

GoogleCodeExporter commented 9 years ago 
Perhaps this is related to this topic?
http://bulletphysics.org/Bullet/phpBB3/viewtopic.php?f=9&t=3783

Can you use the latest Bullet svn repo and export your setup to a .bullet file 
(http://tinyurl.com/yhefmtr) and attach it?

Thanks a lot,
Erwin

Original comment by erwin.coumans on 2 Mar 2010 at 9:31

GoogleCodeExporter commented 9 years ago 
The bug occured in the sio2 game engine on mac os. I can not reproduce the bug 
inside
blender. As I just recognized, sio2 uses a modified bullet implementation. I 
will try
to figure out if the bug is caused by their modification.

Original comment by jont...@googlemail.com on 2 Mar 2010 at 10:29

GoogleCodeExporter commented 9 years ago 
Ok, found the bug. Rotation vector was set by program with invalid values that 
caused
bullet to create strange behaviour. Not the fault of bullet.

I don't know why changing the box-box collision code corrected parts of the 
strange
behaviour, might be coincidence.

Issue can be closed.

Original comment by jont...@googlemail.com on 3 Mar 2010 at 5:17

GoogleCodeExporter commented 9 years ago 
Thanks for the feedback, glad it works for you now.

Original comment by erwin.coumans on 3 Mar 2010 at 8:51