In their website havok says that you need to pay a minimum of $50k per product to use their physics engine. Unity says that I need a Pro license to use Havok in their docs.
So should I pay for both Pro license + additional $50k to havok to use Havok physics with unity?
Also I wanted to test Havok Physics to see if it fixes some specific problem that I have with Unity Physics, but it does not work at all.
Does this mean that I should have a Pro license for it to work inside Unity Editor at all?
Havok Physics for Unity is available to Pro, Enterprise, and Unity Industrial Collection users.
You would only need the $50k Havok license if you use it elsewhere or want source access etc.
Whether you should buy Havok or Unity Pro is entirely up to you. Merely based on the hope that it might fix an issue for you? Probably not, unless the Pro fee is pocket money for you or you have other reasons to go Pro.
Havok’s website has more straightforward details than Unity’s website. Basically a Unity Pro (and I assume Enterprise and Industry too) license gives you access to the binary for both in the editor and in builds. It doesn’t include cloth simulation or pathfinding at the time of the blog post. Looking at the API docs that appears to still be the case. Also any support is only available from Unity. Havok won’t help if you have a problem.
You don’t need the $50k option. You need Unity Pro, that’s it.
And since you would need Unity Pro anyway, then just get Pro and spend just one-twentieth of that money, test-drive everything, and see if you’re good.
The question really is whether you absolutely need Havok because you said yourself, you’re hoping it might fix something which is not a good reason to spend any non-trivial amounts of moneys.
Perhaps open a thread describing the problem and we might have a solution for it. Or might tell you that nothing in the world could fix it.