Maniphest T76827

Select Random Faces assigned to GROUP are not returned at the same position
Closed, Archived
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Assigned To
Alaska (Alaska)
Authored By
kotiel elbaz (kotiel)
May 17 2020, 12:13 PM
Tags
  • BF Blender
Subscribers
Alaska (Alaska)
kotiel elbaz (kotiel)

Description

System Information
Operating system: WINDOWS10 LINUX(arch)
Graphics card: NVIDIA 1650

Blender Version
Broken: (example: 2.80, edbf15d3c044, master, 2018-11-28, as found on the splash screen)
2.90.2 blender-2.90-eaf7d36d66e5-windows64
Worked: (newest version of Blender that worked as expected)

Short description of error
Random Selected faces assigned to a Group - then do a Select (object data properties) returns not the faces assigned to the Group

Exact steps for others to reproduce the error
Based on the default startup or an attached .blend file (as simple as possible).
Default install
SHIFT A Ico-SPHERE subdivisions 5 radius 15
EDIT MODE FACE - SELECT RANDOM
object properties (properties tab) add group - assigned RANDOM SELECTED FACES - ALT A - press SELECT
the FACES selected are not the same as the ones assigned
and some edges are selected.

Tried on linux and Windows 10, version 1909

Cheers
K.

Event Timeline

kotiel elbaz (kotiel) renamed this task from Select Randpm Faces assigned to GROUP are not returned at the same position to Select Random Faces assigned to GROUP are not returned at the same position.May 17 2020, 12:13 PM
kotiel elbaz (kotiel) created this task.
Alaska (Alaska) closed this task as Archived.EditedMay 17 2020, 12:37 PM
Alaska (Alaska) claimed this task.
Alaska (Alaska) added a subscriber: Alaska (Alaska).

I am able to reproduce the issue, but do not believe this is a valid bug. This is because you are assigning the faces to a vertex group. Vertex groups only work on vertices so your face selection is converted to vertex selection and in the process some of the "fine details" in the face selection is lost as some types of face selection can not be described by a vertex selection.

With vertex and face select, you can select the same vertices, but end up with entirely different results. In the screenshot below, the same vertices are selected, but I have entirely different results. There is also no way I can recreate the selection I have in face select mode with vertex select mode.


This kind of information is not stored in the vertex group and so it's lost resulting in the issue you reported.

The way you can tell what your selection will look like when you add it to a vertex group is to select everything you want, then convert to vertex selection mode and now your selection will show what's going to be stored in the vertex group. In most cases if you've selected things with edge or face select mode, the selection will appear to increase. The issue you're experiencing. The selection isn't actually increasing, it's just that some of the details in face and edge select are lost.

I'm sorry if my explanation doesn't make much sense. But I'm fairly confident in my decision to close this report.

kotiel elbaz (kotiel) added a comment.May 17 2020, 12:47 PM

Hi Alaska

Thanks, but
If you select manually the faces and assigned them to the GROUP it WORKS.
FACES are Vertex and it's used with CTRL-I / CTRL-+ to pre-select area of your objects
This feature is mandatory but doesn't work in RANDOM mode.

Cheers
K.

Alaska (Alaska) added a comment.EditedMay 17 2020, 12:54 PM
In T76827#933239, @kotiel elbaz (kotiel) wrote:

Hi Alaska

Thanks, but
If you select manually the faces and assigned them to the GROUP it WORKS.
FACES are Vertex and it's used with CTRL-I / CTRL-+ to pre-select area of your objects
This feature is mandatory but doesn't work in RANDOM mode.

Cheers
K.

I am able to reproduce the issue you described in your original post with manually selected faces. Here's a video example:

And once again, it's because only the information of the vertices that are selected are being stored. And as a result the selection appears to increase when in reality it's not. It's just that the selected faces from the selected vertices is not saved to the vertex group as the vertex group can only store the data of the selected vertices.

kotiel elbaz (kotiel) added a comment.May 17 2020, 1:15 PM

Thanks
fair enough
Please add it to a TODO list

Vertex Group rebranded Group and agnostic about Vertex, Edges or Faces
to select specific area of your object it's a dream with extrude individual faces or particles (weight paint is not enough)

Cheers
K.

Alaska (Alaska) added a comment.May 17 2020, 1:27 PM

I'm not part of the Blender development group. As a result, I am unable to add this to any TODO list. If you would like to make a feature request for this, please do so on https://blender.community/c/rightclickselect/

However, the Blender developers may read this post and add it to a TODO list.