Maniphest T93702

Curve Modifier on mesh objects uses curve before any modifications on target curve
Closed, Archived
Actions

Assigned To
None
Authored By
Nimja (Nimja)
Dec 5 2021, 3:14 PM
Tags
  • BF Blender
Subscribers
Hans Goudey (HooglyBoogly)
Nimja (Nimja)

Description

System Information
Operating system: Windows 10 - Probably irrelevant.

Blender Version
Broken: 3.0.0 (not checked earlier versions).
Worked: (none)

Short description of error
Curve Modifier on mesh objects uses curve before any modifications on target curve, so geometry nodes or other modifiers that change the curve are not reflected in the mesh (which should follow the curve)

Exact steps for others to reproduce the error
See attached blend file for easy example:

bug - curve modifier.blend761 KBDownload

  • Bezier Curve, with some subdivision with a "wave" modifier.
  • Cube .1m with loop cuts to follow curve
  • Cube: Add Array modifier and Curve modifier, targeting the bezier curve

Expected result: Mesh follows waved curve.
Actual result: Mesh follows original (unmodified) curve.

This doesn't work with Geometry nodes or any other modifiers that I've tested for the curve.

Event Timeline

Nimja (Nimja) created this task.Dec 5 2021, 3:14 PM
Nimja (Nimja) updated the task description.Dec 5 2021, 3:18 PM
Nimja (Nimja) updated the task description.
Hans Goudey (HooglyBoogly) closed this task as Archived.Dec 5 2021, 10:36 PM
Hans Goudey (HooglyBoogly) added a subscriber: Hans Goudey (HooglyBoogly).

Thanks for the report. This isn't a bug though, just something that Blender's interface doesn't make very clear. In short, the wave modifier doesn't work on curves, so the curve is implicitly converted to a mesh so the modifier can work on it. If you want it to affect the curve, you can toggle this little option in the modifier header:


Geometry nodes is meant to significantly improve this situation, since deformation can work on any geometry type, and because it's much more clear when a curve becomes a mesh.

Nimja (Nimja) added a comment.Dec 5 2021, 11:56 PM
In T93702#1265652, @Hans Goudey (HooglyBoogly) wrote:

Thanks for the report. This isn't a bug though, just something that Blender's interface doesn't make very clear. In short, the wave modifier doesn't work on curves, so the curve is implicitly converted to a mesh so the modifier can work on it. If you want it to affect the curve, you can toggle this little option in the modifier header:


Geometry nodes is meant to significantly improve this situation, since deformation can work on any geometry type, and because it's much more clear when a curve becomes a mesh.

Actually, the Wave Modifier works just fine in 3.0 with curves :) That's not the point. With Geometry nodes the SAME issue persist.

If you APPLY the curve, it updates the mesh.

You can see the curve itself being in a different place than the mesh in the uploaded blend file. I could make an example with Geometry nodes as well, but I was lazy.