I seen havok in the list is it better than built in physics or the e.g. cans can still fall through on continuous detection if the floor is a plane when navmesh agent steps on it?(rare but still there is overall something wrong with built in), is it available for non commercial use?
Are there rocks or i can even keep the existing props with rigidbodies?
AFAIK there is no official pricing for the Havok Physics engine.
You need to ask them, I guess: https://www.havok.com/request-evaluation/
Edit: Here is a better source of information: Licensing Model | Havok Physics for Unity | 1.3.10
If I understand it correctly, you can use it if you have Unity pro without additional costs.
“Havok Physics for Unity can be downloaded from the Unity Package Manager, but only Pro, Enterprise and UIC users have access to use the features at runtime.”
Okay as i understood it only works in editor (can’t Build or use after play press)? If you download it with personal, though strange why it wasn’t removed from personal users list, maybe it is now, but i remember that i saw the description saying about rigidbodies while i was in Editor, maybe now there is some ECS only thing.
Anyways, the answer is: No you can’t use it for non-commercial use for free
(At least with personal license)
And extra, i bet it still doesn’t magically fix problems, you still need own code to fix physics and avoid all fall throughs, especially on discrete, lowest compute costs collisions. I guess even Source engine physics aren’t just raw Havok, considering it was 2003-4 also, when they finished setting it up.