Feature: Extra Examples (outside a simple the viewer)?

[rohit-kumar-j]

I'm currently working with masse, torques, etc, seeing this series. And was hoping to take the examples directory a bit further (Although I'm not sure how much of this is practical). By creating sort of a tutorial/example with a simple pendulum to obtain units of torque, tuning values of kp, kd, ki etc...
A graphing of PID error like the profiler/sensor section of the simulate viewer which generates live graphs.

Perhaps a wiki with these:

• 4-bar-mechanism example, for creation of constraints
  4-bar-example
• Simplified mujoco_viewer.py in extended-example-tutorial commits: 97783ab 5839301 aab2d48
• Add Sensor Graphs : Preview
• PID tuning and example in wiki mujUI elements are not supported yet in python

Existing graphing:

[rohanpsingh]

Add Sensor Graphs

I understand that you want to add more features in the current viewer, but please note that there is an ongoing effort in the official mujoco github to create python bindings for simulate.cc: google-deepmind/mujoco#201
Once that is merged, there would most probably be no need for mujoco-python-viewer :)

[rohit-kumar-j]

I did not see that. It would be nice to have the simulate viewer in python that is officially supported. Nevertheless, I intended to create a slightly different viewer than simulate(similar to gazebo's pid tuning) and mujoco-python-viewer gave a good starting point.

[rohit-kumar-j]

Added graph rendering for viewing, although UI elements for python are not supported in the mujoco yet #23