Copy only dynamic data

[majklost]

I am using pymunk for my bachelor thesis, where I plan using RRT algorithm. Problem is, that I store many copies of space in a tree. I benchmarked my solution and found out that making a copy of space is the most expensive operation in whole process (70 % of time). Since all the simulations contain same bodies, constraints, shapes and collision handlers, I would just need to extract and apply only data that changes when stepping the simulation.

I tried to copy all physical aspects of bodies to bodies in second simulator (pos, velocity, angle,...), But simulation result still differs.... I looked how space.copy() is implemented, but it creates new space, so many things differs from my usecase.

Can you give a hint what all should I export and import from one simulation to another to achieve same behaviour when stepping both of them? (I can then contribute this feature to pymunk if it works) Thanks, Michal