Hi eric, the first v4 beta will not have dimensions yet, it will have the same features as v3 initially except that it will be 64-bit and a native Mac build.

After the first beta is out then I'll be working on new features and basic dimensions are high on my radar so I hope to be able to work on them during the beta period. But I don't know exactly when they will be implemented or how they will interact with Rhino dimensions yet, I won't know more details about that area until I've been able to spend some time on it.

- Michael