The licensing and distribution model of Havok Physics for Unity is owned and managed entirely by Microsoft (Havok) and not by Unity.
Havok Physics for Unity is free to download from the Unity Package Manager. Using the features at runtime may, however, require a development license depending on your Unity subscription plan:
- Unity Personal: Free to use.
- Unity Plus: Free to use.
- Unity Pro: Havok Physics for Unity subscription is required, available from the Unity Asset Store.
When using this package, the Unity Editor will periodically check if you are entitled to use the runtime features. The runtime features will be locked if you are not signed into Unity, or you are a Unity Pro user without a valid subscription. Once unlocked, there is an allowance for working offline as the same user for up to one month before the subscription must be reconfirmed.
Note that the runtime features are always unlocked for standalone applications that have been built from Unity. Standalone applications do not require an Internet connection for Havok Physics for Unity to function.