Creating a customized IK-solver

[Daniel Krueger]

Hello,
I am looking for a way to perform inverse kinematics of underdetermined systems. In particular i want to use as few constraints (markers) as possible to solve for a suitable set of coordinates. The idea is to use some kind of scalar objective function to determine an optimal solution in the coordinate space. I figured out that OpenSims assmbly solver does not provide this functionality. I came up with two possible solutions:
-Is it possible to replace the default assembly solver with a custom class? Maybe as a plugin?
-Can I access the constraint equations of OpenSim and Simbody constraints in order to provide them to my own external IK-solver?

I am using OpenSim for comfort analyses in product design and want to improve the interactive posing capabilities.

bye,
daniel

[Daniel Krueger]

In the meantime I found a solution for my problem: At the level of simbody it is possible to specifiy custom assembly goals for the kinematic assembler. I already testet it and think it will be useful. The only drawback I see is that an OpenSim:Model always creates its own simbody assembler which cannot be accessed through the API and therefore will remain inside the model along with the customized assembler. So one has to be careful not to call any methods (like Coordinate.setValue) that invoke the models assembly solver!
Greets,
Daniel

[Daniel Krueger]

By the way: Thank You Ayman for the offer to get the source code! This will solve the coexistence of multiple assemblers.
best regards,
Daniel