Delete Geometry node does not preserve Vertex Crease data #100689

New Issue

Rainer Trummer · 2022-08-29T14:34:33+02:00

Rainer Trummer commented

2022-08-29 14:34:33 +02:00

System Information
Operating system: Windows-10-10.0.19042-SP0 64 Bits
Graphics card: Quadro RTX 4000/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 513.29

Blender Version
Broken: version: 3.4.0 Alpha, branch: master, commit date: 2022-08-29 07:47, hash: 613b6ad9e5
Worked: none afaik

Short description of error
When using Vertex Creases, the delete geometry node completely discards that crease data. You can see this in the demo file provided here:
DeleteGeoBug.blend
On one corner I used edge creases to harden the corner, on the other corner I used vertex creases. Edge creases remain intact after delete geometry, vertex creases are lost. The corner underneath should be sharp (and is so if you mute the delete geometry node in the the geometry nodes modifier):

Exact steps for others to reproduce the error
[Please describe the exact steps needed to reproduce the issue]
[Based on the default startup or an attached .blend file (as simple as possible)]

**System Information** Operating system: Windows-10-10.0.19042-SP0 64 Bits Graphics card: Quadro RTX 4000/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 513.29 **Blender Version** Broken: version: 3.4.0 Alpha, branch: master, commit date: 2022-08-29 07:47, hash: `613b6ad9e5` Worked: none afaik **Short description of error** When using Vertex Creases, the `delete geometry` node completely discards that crease data. You can see this in the demo file provided here: [DeleteGeoBug.blend](https://archive.blender.org/developer/F13430350/DeleteGeoBug.blend) On one corner I used edge creases to harden the corner, on the other corner I used vertex creases. Edge creases remain intact after `delete geometry`, vertex creases are lost. The corner underneath should be sharp (and is so if you mute the `delete geometry` node in the the geometry nodes modifier): ![delete_geometry.jpg](https://archive.blender.org/developer/F13430354/delete_geometry.jpg) **Exact steps for others to reproduce the error** [Please describe the exact steps needed to reproduce the issue] [Based on the default startup or an attached .blend file (as simple as possible)]

Rainer Trummer commented

2022-08-29 14:34:33 +02:00

Added subscriber: @RainerTrummer

Omar Emara commented

2022-08-29 16:47:47 +02:00

Changed status from 'Needs Triage' to: 'Confirmed'

Philipp Oeser commented

2022-08-31 09:56:56 +02:00

Added subscriber: @lichtwerk

Philipp Oeser commented

2022-08-31 09:56:56 +02:00

Seems there is a nameclash between two attributes (we a crease attribute on both ATTR_DOMAIN_POINT AND ATTR_DOMAIN_EDGE)

copy_attributes_based_on_map cant handle that (it earlies out when finding the crease attribute on the wrong domain -- even disabling that would then cause the GSpanAttributeWriter to write to the other domain).
Assume AttributeAccessor lookup/ lookup_or_add_for_write_only_span could be tweaked to take domain into account?
Will check...

Seems there is a nameclash between two attributes (we a `crease` attribute on both `ATTR_DOMAIN_POINT` AND `ATTR_DOMAIN_EDGE`) `copy_attributes_based_on_map` cant handle that (it earlies out when finding the `crease` attribute on the wrong domain -- even disabling that would then cause the GSpanAttributeWriter to write to the other domain). Assume `AttributeAccessor` `lookup`/ `lookup_or_add_for_write_only_span` could be tweaked to take domain into account? Will check...

Jacques Lucke commented

2022-08-31 10:05:05 +02:00

Added subscriber: @JacquesLucke

Jacques Lucke commented

2022-08-31 10:05:05 +02:00

Didn't look into it in detail, but I think the main issue might be that the attribute system just doesn't know about vertex creases yet. That's mainly because it is not a generic custom data layer type (like CD_PROP_FLOAT), but uses CD_CREASE. For edge creases we already added special handling in create_attribute_providers_for_mesh.

Didn't look into it in detail, but I think the main issue might be that the attribute system just doesn't know about vertex creases yet. That's mainly because it is not a generic custom data layer type (like `CD_PROP_FLOAT`), but uses `CD_CREASE`. For edge creases we already added special handling in `create_attribute_providers_for_mesh`.

Philipp Oeser commented

2022-08-31 10:10:12 +02:00

In #100689#1410474, @JacquesLucke wrote:
Didn't look into it in detail, but I think the main issue might be that the attribute system just doesn't know about vertex creases yet. That's mainly because it is not a generic custom data layer type (like CD_PROP_FLOAT), but uses CD_CREASE. For edge creases we already added special handling in create_attribute_providers_for_mesh.

Seems the CD_CREASE attribute comes into copy_attributes_based_on_map just fine, so AttributeAccessor seems to handle it already?

> In #100689#1410474, @JacquesLucke wrote: > Didn't look into it in detail, but I think the main issue might be that the attribute system just doesn't know about vertex creases yet. That's mainly because it is not a generic custom data layer type (like `CD_PROP_FLOAT`), but uses `CD_CREASE`. For edge creases we already added special handling in `create_attribute_providers_for_mesh`. Seems the `CD_CREASE` attribute comes into `copy_attributes_based_on_map` just fine, so AttributeAccessor seems to handle it already?

Philipp Oeser commented

2022-08-31 10:18:56 +02:00

Maybe spoke too soon, seems like skipping copy_attributes_based_on_map alltogether does not really make a difference, so edge creases still survive without that...

Maybe spoke too soon, seems like skipping `copy_attributes_based_on_map` alltogether does not really make a difference, so edge creases still survive without that...

Philipp Oeser commented

2022-08-31 10:28:00 +02:00

Edge creases seem to survive because it still sits on the MEdge , vertex creases dont sit on the MVert though but in a custom data layer. MEdge & MVert get copied over 1:1 outside attribute handling.

See also

/**

Usage of #CD_CREASE depends on where on the Mesh the layer is added:

For vertex creasing, this is persistent data across all modes and is stored in the file.

For edge creasing, it is runtime data which is only used in edit-mode before being copied

to #MEdge when exiting edit-mode.
*/

This is probably no news to any dev involved, so will quit sinking in more time, this is probably handled better by @JacquesLucke

Edge creases seem to survive because it still sits on the `MEdge` , vertex creases dont sit on the `MVert` though but in a custom data layer. `MEdge` & `MVert` get copied over 1:1 outside attribute handling. See also > /** > * Usage of #CD_CREASE depends on where on the Mesh the layer is added: > * - For vertex creasing, this is persistent data across all modes and is stored in the file. > * - For edge creasing, it is runtime data which is only used in edit-mode before being copied > * to #MEdge when exiting edit-mode. > */ This is probably no news to any dev involved, so will quit sinking in more time, this is probably handled better by @JacquesLucke

Hans Goudey commented

2022-08-31 18:20:04 +02:00

Added subscriber: @HooglyBoogly

Hans Goudey commented

2022-08-31 18:20:04 +02:00

For now I think this is a known issue.
IMO the best solution is to improve generic attribute editing and to make vertex and edge crease into generic attributes.

For now I think this is a known issue. IMO the best solution is to improve generic attribute editing and to make vertex and edge crease into generic attributes.

Philipp Oeser removed the

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Delete Geometry node does not preserve Vertex Crease data #100689