Motivation

Our minimal experimental blueprint APIs allow you to explicitly list specific entities to add to a space-view, but this can be quite cumbersome with large scenes. We would like to be able to add an entire sub-tree (or other complex expression) through a single API call.

Approach

Because the Blueprint needs to be set before logging data, there is no way to do this with a mechanism such as a log-time query that resolves to a collection of entity-paths. It must be stored in the blueprint representation as a query which is evaluated at runtime.

Rather than the SpaceViewContents structure used today, which explicitly stores all of the entities within a scene, we will introduce a new "Data Query" concept which evaluates the parts that will be shown in the the space-view at runtime.

• See: the notion proposal for more details.

Sub-tasks

• Implement DataQuery trait and wrap SpaceViewContents for backwards compatibility.
• Refactor SpaceView to consume DataResultTree.
• Replace DataBlueprintGroup with new Property override system that works on DataResultTree.
• Refactor BlueprintTree to consume DataResultTree.
• New DataQuery implementation to produce DataResultTree from wild-card
• MVP Blueprint API for adding DataQuery to the blueprint.

Follow-up tasks:

• Update DataResultTree to start at origin and introduce "projected" subspace #4156
• UI workflow for adding DataQuery with query expression #4157
• Support for subtractive / filter rules in DataQuery #4158