Debug your Bullet Project
From Physics Simulation Wiki
Debugging your bullet project can be hard, that is why we wrote a guide for you to explain what tools you have and what key issues you might have and how to fix them.
The bullet debug drawer draws information about your bullet objects as an overlay to your simulation. It helps to visualize mismatch between your Bullet objects and your visualizations. Furthermore, it visualizes the joints and joint limits, contact points etc. Here is an extended article on the Bullet Debug drawer.
TODO: Describe how to use the bullet profiler.
Here are several key problems your project could have and what to do about it.
Problem: Simulating the same thing multiple times in my project does not always produce the same outcome.
Solution: Your project does not run deterministically. Fix your project using the article on Determinism.