Scene graph / editor

[funwithtriangles]

Currently, when you add a sketch to a scene, the root object for the sketch gets added to the top level of the scene. From inside Hedron, you have no control over the position of this root object or any sort of hierarchy. We can do better than this!

Hedron scene graph

• Users should be able to see a basic overview of their scene. The camera, lights and various sketches.
• Position/rotation/scale of each element should be controllable like params
• Sketches could possibly have child sketches
• "Empties" should be available to hold many children
• Sketches could possibly "register" elements as children, so those are also easily positioned
• Sketches without a root object are "unattached" and sit outside of the scene graph
• Users should have the option to see this scene graph or just the usual flat list of sketches.

Editor
With a Blender style scene graph, we'd also expect an editor view of the scene. We'd need an extra camera, only for the purposes of previewing the scene (not available in the scene graph). We could also have proper widgets on screen for editing transformations of elements.

In order to achieve the above, we'd need to take a good look at the general layout of Hedron and how we can accommodate for such complexity. Having a "compose" mode and a "show" mode might be needed.