[ODE] Body and object origin

[Martin C. Martin]

The origin of the box body must be at the center of mass.  

Look into the transform geom.

- Martin

Frederic Ferland wrote:
> 
> I have a fancy lamp hanging from the ceiling in a room in my engine.  It is
> shaped more or less like a capital T that's been rotated 180 degrees.  The
> origin of the object is at the extremity of the rope that attaches the
> object to the ceiling.
> 
> I create two box geoms to represent the object.  One is long and tall (for
> the rope) and the other is large and thin (for the bottom part of the
> lamp).  I also create a box body and attach the lamp to the ceiling using a
> ball joint.
> 
>                -----------  <--- Box body
>                I         I
>                I    * <--I--- Object origin
>                I    *    I
>                -----*-----
>                     *
>                     *
>                     *
>                     *
>            =========*===========
> 
> When I run my program, everything is fine and the lamp hangs and swings
> from the ceiling like I intended.  However, if I break the joint so that
> the lamp falls on the floor, it tries to 'stand' on it's rope instead of
> staying flat on it's bottom part like it would in real life, because the
> box body is centered on the object's origin rather than on what should
> normally be the heavy part of the object.
> 
> My question is, do I have to change my object's origin so that it's in the
> bottom part of the lamp instead of the rope, or is there a way to have ODE
> distribute the weight of the body towards the bottom part instead of at the
> extremity of the rope?  In other words, can I somehow offset the ODE body
> like I offset the geoms?
> 
> Hope all this lengthy explanation is clear to everyone... :)  Thanks for
> your help!
> 
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