I hope you don't mind if I ask for a bit of advice regarding modelling robotic systems. I've recently become rather interested in using inverse kinematics (IK) to control a 5 dof robotic manipulator. I have a solid foundation in IK but what I'm having trouble with is a way to visualize how the manipulator moves with respect to joint angles.
I've looked into using 3D toolkits (such as Blender, Panda3D, vPython) to create a 3d model of the arm, but I'm not sure if I should be looking something with physics support. I'm also not sure how well I can model motion with these packages. Anyone have any suggestions? What I'm NOT looking for is a full blown robotic simulator like Microsoft's Robotic Studio, I'd like to start with the basics and learn how everything works first, ie code the IK in Python, then visualize the motion in 3D. I'm very familiar with Python, so something that interfaces with Python would be preferable.
Well the great thing about Blender is that its API is actually in python!
In addition, it supports inverse kinematics (IK) quite well in addition to many other modeling tools.
Blender Cookie is a great resource.
Here is a tutorial on making IK rigs in Blender.
Blenders python api is documented quite extensively, and it even has an interactive python shell built right in so that you can see the effects of your script as you go along.
The physics engine that blender uses is the popular bullet physics engine, which has been used in many commercial games as well as a few feature films (2012 among them).