Maniphest T104262

Geonodes can't be applied on top of Multires while the displace modifier can be applied
Closed, Archived
Actions

Assigned To
None
Authored By
kursad k (kursadk)
Tue, Jan 31, 7:36 PM
Tags
  • BF Blender
  • Nodes & Physics
  • Geometry Nodes
  • Modeling
  • Modifiers
Subscribers
Hans Goudey (HooglyBoogly)
Iliya Katueshenock (Moder)
Julien Kaspar (JulienKaspar)
kursad k (kursadk)
ronan ducluzeau (zeauro)

Description

System Information
Operating system: Windows

Blender Version
Broken: 11de4aa0cea7

Short description of error

When the user applies a geonodes modifier that displaces the vertices, it is applied to the base mesh while a displacement modifier can be applied on top of a multires modifier. This is an important use case, and we should retain the ability to applying modifiers on top of the Multires modifier if the displacement modifier is discarded in the future in favor of the geonodes setups.

Exact steps for others to reproduce the error

Load the attached .blend

Apply the displacement modifier

Undo

Apply the geo nodes

Observe the difference.

_31012023_1225_17.zip4 MBDownload

Related Objects

Mentioned Here
T101778: Node group operators
rB11de4aa0cea7: Update RNA to User manual mappings

Event Timeline

kursad k (kursadk) created this task.Tue, Jan 31, 7:36 PM
kursad k (kursadk) updated the task description.
Iliya Katueshenock (Moder) added projects: Nodes & Physics, Geometry Nodes, Modeling, Modifiers.Tue, Jan 31, 7:47 PM
Iliya Katueshenock (Moder) added a subscriber: Iliya Katueshenock (Moder).

Hello. There are several groups of modifiers. these are the columns in the add modifier menu. And it has real technical limitations.
Generation modifiers mean exactly that they can't just deform something.

kursad k (kursadk) added a comment.Tue, Jan 31, 9:00 PM

@Iliya Katueshenock (Moder) I understand that but bear in mind I am only displacing points not generating new geometry or messing with the polygon data. It is basically doing what a displace modifier does, see the image.

Iliya Katueshenock (Moder) added a comment.Tue, Jan 31, 9:07 PM

It is too difficult to check this in the general case. Geometry nodes are just a generator.

ronan ducluzeau (zeauro) added a subscriber: ronan ducluzeau (zeauro).EditedThu, Feb 2, 12:30 PM

Geometry Nodes can be used as Deform modifiers, as much as Generate modifiers.

So, user should have both options.

There could be a check to know if polycount have been changed by modifier.
In that case, Apply option would apply on base mesh like a Generate modifier.
If there is no change of polycount, Apply option would apply on multires level like a Deform modifier.

If it is too complicated to have an automatic check, or if there is a fear of case of a generation done with a decimation, giving same polycount ; choice could be given to the user.
There could be an Apply as Multires Level option like there is an Apply as Shape Key option, only available for Deform modifier.
That solution would have advantage to be more discoverable than apply-on-level-below-the-highest-one trick working, when an attempt of an apply-on-highest-level triggers a pop-up message, saying that is not possible.

Geometry Nodes could be an exception in Generate modifiers list and could support these options.

Iliya Katueshenock (Moder) closed this task as Archived.Thu, Feb 2, 12:32 PM
Julien Kaspar (JulienKaspar) added a subscriber: Julien Kaspar (JulienKaspar).Fri, Feb 3, 2:37 PM

@kursad k (kursadk) @ronan ducluzeau (zeauro) This is noted down as an important use case for the future multires rewrite, also in relation to T101778.
Multires needs to become more accessible for other parts of Blender and there are already discussions on integrating it with geometry nodes.
But this is outside of the scope of the current projects and not a bug.

Hans Goudey (HooglyBoogly) added a subscriber: Hans Goudey (HooglyBoogly).Fri, Feb 3, 2:46 PM

there are already discussions on integrating it with geometry nodes

Interesting, is anything written down on that topic? I wasn't aware people were thinking about that.

kursad k (kursadk) added a comment.Fri, Feb 3, 10:47 PM

@Julien Kaspar (JulienKaspar) Thanks for the additional information and attention to this bug.