Shrinkwrap Offset behaves weird. #88232

New Issue

Albert · 2021-05-12T17:57:45+02:00

Albert commented

2021-05-12 17:57:45 +02:00

System Information
Operating system: Windows-10-10.0.19041-SP0 64 Bits
Graphics card: GeForce GTX 1060 3GB/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 460.89

Blender Version
Broken: version: 3.0.0 Alpha, branch: master, commit date: 2021-05-11 21:46, hash: 65244ac1c3
Worked: (newest version of Blender that worked as expected)

Short description of error
To put over the new mesh on top of the old base, it would be enough to move it outwards with the Shrinkwarp offset, but the vertices previous the subdivision act in a strange way. For this reason I usually add a displace.
Although I can solve the problem with the Displace, I consider that Shrinkwarp does not act as it should.

Exact steps for others to reproduce the error
For the base create a monkey, subdivide it, and apply the modifier.
For the retopology mesh, create a plane, add the modified subdivision with two simple subdivisions, add Shrinkwrap and set Offset to -0.03.
Activate Snap to Face with Project Individual Elements.
Extrude and shift some edges.RetopoError.blend

RetopoError.mp4

**System Information** Operating system: Windows-10-10.0.19041-SP0 64 Bits Graphics card: GeForce GTX 1060 3GB/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 460.89 **Blender Version** Broken: version: 3.0.0 Alpha, branch: master, commit date: 2021-05-11 21:46, hash: `65244ac1c3` Worked: (newest version of Blender that worked as expected) **Short description of error** To put over the new mesh on top of the old base, it would be enough to move it outwards with the Shrinkwarp offset, but the vertices previous the subdivision act in a strange way. For this reason I usually add a displace. Although I can solve the problem with the Displace, I consider that Shrinkwarp does not act as it should. **Exact steps for others to reproduce the error** For the base create a monkey, subdivide it, and apply the modifier. For the retopology mesh, create a plane, add the modified subdivision with two simple subdivisions, add Shrinkwrap and set Offset to -0.03. Activate Snap to Face with Project Individual Elements. Extrude and shift some edges.[RetopoError.blend](https://archive.blender.org/developer/F10088347/RetopoError.blend) [RetopoError.mp4](https://archive.blender.org/developer/F10088345/RetopoError.mp4)

Albert commented

2021-05-12 17:57:45 +02:00

Added subscriber: @wevon-2

Philipp Oeser commented

2021-08-20 12:08:06 +02:00

Added subscriber: @lichtwerk

Philipp Oeser commented

2021-08-20 12:08:06 +02:00

Changed status from 'Needs Triage' to: 'Needs User Info'

Philipp Oeser commented

2021-08-20 12:08:06 +02:00

Hi and thx for the report! (sorry it took a while to answer)

This looks weird on first sight, yes.
But: I think this is actually intended behavior.

From
https://docs.blender.org/manual/de/dev/modeling/modifiers/deform/shrinkwrap.html

On Surface
The vertex is always moved. The offset is applied along the projection line connecting the original vertex and selected target point towards the original position.

In your case the original points of the cage already sit exactly on the surface (due to snapping). Which results in the offset being applied on a zero-length line (so they wont get an offset at all). The points resulting from the subd however have a distance between their original position and the surface (so they will get an offset).

Suggest to use this instead:

Above Surface
Like On Surface, but the offset is applied along the smooth normal of the target.

This way, offset is applied in direction of the normal (which is always ensured to have a non-zero length).

Does this work for you?

Hi and thx for the report! (sorry it took a while to answer) This looks weird on first sight, yes. But: I think this is actually intended behavior. From https://docs.blender.org/manual/de/dev/modeling/modifiers/deform/shrinkwrap.html > On Surface > The vertex is always moved. The offset is applied along the projection line connecting the original vertex and selected target point towards the original position. In your case the original points of the cage already sit exactly on the surface (due to snapping). Which results in the offset being applied on a **zero-length** line (so they wont get an offset at all). The points resulting from the subd however have a distance between their original position and the surface (so they will get an offset). Suggest to use this instead: > Above Surface > Like On Surface, but the offset is applied along the smooth normal of the target. This way, offset is applied in direction of the normal (which is always ensured to have a non-zero length). Does this work for you?

Albert commented

2021-08-20 18:13:01 +02:00

Thanks Philipp for keeping an eye on it and answering me.

With Above Surface and with a positive Offset value, it works perfectly for me.

Well seen.

Thanks Philipp for keeping an eye on it and answering me. With Above Surface and with a positive Offset value, it works perfectly for me. Well seen.

Philipp Oeser commented

2021-08-20 18:29:40 +02:00

Changed status from 'Needs User Info' to: 'Archived'

Philipp Oeser closed this issue

2021-08-20 18:29:40 +02:00

Philipp Oeser commented

2021-08-20 18:29:40 +02:00

OKi, thx getting back, will close then.

Sign in to join this conversation.

No Label

Download

What's New

Blender Studio

Manual

Developers Blog

Documentation

Benchmark

Blender Conference

Development Fund

One-time Donations

Shrinkwrap Offset behaves weird. #88232