I am still using the AnyBody 6.0 version with the AMMR 1.6 to build my model. I have gotten some problems when i use the FDK model. I use patient-specific data to build the model. I have done nearly all the same as the TKA-kneebend demo but I still cant run the model. When I run the inverse dynamics, there is always an error "Failed to resolve force-dependent kinematics. Too small steps for GSS search causes looping of Newton method (final force error = 8.946040E+001). Continue anyhow..." comes up. When i look into the results, many muscle forces are around e-10N such as VastusLateralisInferior which is extremely large. And there are no contact forces in the tibial medial or lateral implant but the model actually penetrates the femoral component. Many thanks if you could help with my problem.