Varible failing to update

[Katherine_Morrissey]

I am trying to simulate an orbit here. The issue that I’m running into is that my momentum variable is not updating. I have checked that Gravitaitonal_force and dt are non 0 values so it seems like it just won’t update. What do I do?

[bollwyvl]

This is more of a general python question, and whatever libraries you be using (which we can’t see in the screenshot)… as some of them have .x, they aren’t just numbers.

Ideally, post this as a gist such that someone could actually reproduce your issue.