Currently, a space view has a single category that is determined once at creation.
It governs what the space view looks like/how it's renderer and how interaction works with it. Additionally, it imposes restrictions on which Entities can be added (we compute a list of categories from each).

The category is determined either by user interaction on creating it or (more common?) by being automatically created through a heuristic.

There are are many cases where it may make sense to choose a different space view after the fact, most prominently Tensor & Spatial view.

There are a lot of open questions related to this, some of which touch on other issues:

• what happens with entities that can no longer or only partially be displayed? How to indicate this?
• how flexible does each category need to be?
• Should 2d & 3d become separate categories again, or stay together in the "spatial" category
• How well integrated should space views be into each other - e.g. is there ever a meaningful way to display a time series in a 3d context? If yes how if no why not.