[ODE] Patch to add a new joint in ODE

[Remi Ricard]

Hi Thomas,

>
>> Hi,
>>
>> I'm only posting this here to let the developers with svn access know
>> that there is a new patch.I submitted the patch on the sourceforge 
>> website.
>>
>> The patch add a new joint to ODE.
>>
>> The new joint is like a slider joint but the bodies are free to 
>> rotate in one direction. The axis of rotation is the same as the 
>> slider axis.
>>
>> The patch include all the modification to ..h and .cpp files.
>> A simple demo demo_piston.cpp and finally patch for the premake.
>>
>> This is a patch against the latest trunk code (revision 1173).
>>
>> The patch was produced with:
>> cd openode; svn diff joint_piston.patch
>>
>>   
> Hi,
>
> I'm surprised there's no dJointSetPistonAnchor method in the patch you 
> submitted (there's only a dJointSetAxis one).
>
> Around wich axis ( a point and 3 vects) is computed the rotation? How 
> is it possible to modify this point location?
>
> Thomas

It was kind of busy here so it took time before finding the good answer.

Before submitting the joint I only tested when body1 and body2 have 
their center of mass as follow
cm1 = cm2 + A x axis_of_prismatic

i.e cm aligned with the axis of the prismatic.

yesterday someone here tested the new joint when there is an offset and 
was also asking about the anchor point.

So I think you are right to have a more general joint an anchor point 
will be needed.
I might have time to had that after you rush for a demo.

For now you can consider the anchor point as the center of body2 if I 
remember correctly.


Remi