PolyStrips: Proportional Edit

[vxlcoder]

(moved here from #1397)

The one nice-to-have but not necessary feature would be the ability to adjust strips that are already connected to other geometry and have a falloff for how much the surrounding geometry is affected. For example:

Given this strip:

Adjusting it currently gives this result:

Whereas, ideally, it would influence the surrounding geometry with a soft falloff based on topological distance.

This would be extremely helpful for adjusting key loops around faces and other organic features. I don't know how hard that is though, so I think it should only be considered after the base functionality is there, if it would be an easy win, and if there is extra time before the release.

[vxlcoder]

@jlampel, this shouldn't be hard to implement, but I have lots of follow-up questions.

should we use the brush size (screen space) to determine what all other verts should be edited?

• if so, would we will need to change PS to always show the brush so the artist knows the affected size?
• or maybe show the brush when hovering a control point?
• should we add Wheel changes brush size while tweaking a handle?

right now, PS Edit transforms the verts uniquely from standard blender grab ops. i suppose i could try to adjust the vert positions by figuring out where each vert should go and iteratively call blender's transform op on each vert. this would allow blender to handle all the proportional editing stuff... but i think it would be very difficult to do this in a sane way. it seems extremly hacky!

alternatively, we write our own version of prop editing.

always the decision: should we use standard blender stuff so it matches, or do our own thing that's much easier to maintain and control?

[vxlcoder]

commit 23af344 is a vertical slice through this as a quick test.

[jlampel]

This is awesome! Thank you!!

I don't think we should use the brush size, since we're always going to want the affected size to be bigger than that and the user would need to be scaling up and down pretty often. Can we just use Blender's scene tool setting Proportional Size? And draw a similar circle only when transforming? It would be really nice if we could just lean on Blender's proportional editing here, but I'm not sure if that's possible.