Bent concave 2D curve triangulation problem w/ modifiers applied #68589

New Issue

Steffen Vetne · 2019-08-13T01:01:16+02:00

Steffen Vetne commented

2019-08-13 01:01:16 +02:00

Broken: 2.80

(I think the problem is triangulation)
Triangulation sometimes has problems with concave shapes, and I believe this is caused by triangulation (without overlaps) being much more difficult in 3d than 2d. But the problem shouldn't really exist (at least in my case) because the triangulation would work fine using 2D triangulation by projecting the points to 2d along the average normal of the face (it bends less than 90 degrees, so 2D triangulation would be perfect).

Open the project, the shape is completely wrong on the flat faces when using the curve modifier. It's supposed to be a concave crescent shape, instead of the convex hull sorta shape it has now.

Broken: 2.80 [BUG.blend](https://archive.blender.org/developer/F7661053/BUG.blend) (I think the problem is triangulation) Triangulation sometimes has problems with concave shapes, and I believe this is caused by triangulation (without overlaps) being much more difficult in 3d than 2d. But the problem shouldn't really exist (at least in my case) because the triangulation would work fine using 2D triangulation by projecting the points to 2d along the average normal of the face (it bends less than 90 degrees, so 2D triangulation would be perfect). Open the project, the shape is completely wrong on the flat faces when using the curve modifier. It's supposed to be a concave crescent shape, instead of the convex hull sorta shape it has now.

Steffen Vetne commented

2019-08-13 01:01:16 +02:00

Added subscriber: @Steffenvy-4

Campbell Barton commented

2019-08-13 09:48:43 +02:00

Added subscriber: @ideasman42

Campbell Barton commented

2019-08-13 09:48:43 +02:00

Changed status from 'Open' to: 'Archived'

Campbell Barton closed this issue

2019-08-13 09:48:43 +02:00

Campbell Barton self-assigned this 2019-08-13 09:48:43 +02:00

Campbell Barton commented

2019-08-13 09:48:43 +02:00

This is a limitation with the current modifier stack.

While there is an option to "Fill deformed", he curve is being rotated before being filled, which causes filling to fail - since filling is done in 2D.

Closing.

This is a limitation with the current modifier stack. While there is an option to "Fill deformed", he curve is being rotated before being filled, which causes filling to fail - since filling is done in 2D. Closing.

Philipp Oeser commented

2019-08-13 10:19:01 +02:00

Added subscriber: @lichtwerk

Philipp Oeser commented

2019-08-13 10:19:01 +02:00

Can confirm triangulation is not great here, maybe @ideasman42 has an idea?

Philipp Oeser commented

2019-08-13 10:30:46 +02:00

Hm, thing is, even if the deforming curve is 2d only as well, then triangulation fails as well... see [Fill deformed is ON here]
BUG_2d_only.blend
@ideasman42: shouldnt this work then, there is no rotation going on then, right?

Hm, thing is, even if the deforming curve is 2d only as well, then triangulation fails as well... see [`Fill deformed` is ON here] [BUG_2d_only.blend](https://archive.blender.org/developer/F7661418/BUG_2d_only.blend) @ideasman42: shouldnt this work then, there is no rotation going on then, right?

Campbell Barton commented

2019-08-13 12:46:40 +02:00

Changed status from 'Archived' to: 'Open'

Campbell Barton reopened this issue

2019-08-13 12:46:40 +02:00

Campbell Barton commented

2019-08-13 12:46:40 +02:00

@lichtwerk you're right, this case should work.

Campbell Barton changed title from ~~Bent concave polygon triangulation problem~~ to Bent concave 2D curve triangulation problem w/ modifiers applied

2019-08-14 13:52:08 +02:00

Campbell Barton was unassigned by Dalai Felinto

2019-12-23 16:33:19 +01:00

Philipp Oeser removed the

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Bent concave 2D curve triangulation problem w/ modifiers applied #68589