Allow certain primitive parameters to be 'animated' by blending them between two values in the viewer.
Interpolated properties could include:
* Color tint (legacy diffuse + PBR base color)
* Glow (legacy + PBR)
* Emissive tint (PBR)
* Point light color
* Point light intensity
* Point light radius
* Point light falloff
* Interpolating textures (e.g. PBR material A to PBR material B) would also open up a lot of interesting use cases, but is a more advanced scenario that shouldn't hold up the more 'basic' parameters if it proves to be too difficult.
Interpolation could include a simple linear blend from A->B over a time period or a "repeat" from A->B->A. Other interpolation types and 'loops' could also be possible.
Many objects have 'special effects' that use tight loops (e.g. 50ms delays) to try to animate things like pulsing glows, pulsing or flashing lights, or blending color hues. Having client side interpolation for these would significantly reduce server load.