leg6dof9musc replay of IK solution has disconnected patella

[aseth1]

Steps to reproduce

• load leg6dof9musc.osim model from Models with distribution.
• load the Swing/leg69_IK_swing.mot motion file
• press play.

Expected result

Swing motion plays and all patella is constrained to the knee.

Actual result

Overall leg motion is correct but the patella does not track the femur.

This seems to be a constraint enforcement issue, because when a coordinate slider is manually adjusted, the patella snaps back into place.

This is likely related to #608 since the vectorized setting of state values does not enforce constraints. It expects that state values were obtained by satisfying constraints. Although IK computes the constrained knee_angle_pat_r value (constrained to be the knee_angle), it does not report the constrained coordinate value, and Model::formStateStorage will use its default value.

The fix here is to add a final Model::assemble(s) for good measure OR detect when the input files are motions (e.g. does not have a complete state) and then do the assemble.

Environment and GUI version

Windows build 0321

[aymanhab]

Thanks for the find @aseth1 Can you advise as to where to assemble()? e.g. right after calling setStateVariableValues? Should we do this only if there are constraints in the model, for efficiency? Also wouldn't that break #540 again if we assemble since constraints will be enforced? Thanks

[aseth1]

Model::assemble() will only assemble if there are constraints. For #540 the fix was to move clamping within the enforce constraints check, so the assemble should not push the values within the bound. What did you observe in #620?

[aymanhab]

Fixed by PR #620, Please verify and close as needed.

[jenhicks]

This is fixed on my Mac (3-26 build)

[jimmyDunne]

Fixed on W10.

Build 04-27-18