'Select Similar' for the UV Editor #47437

Benefits: Artists can more easily isolate parts of the UV map to operate on, using a selection method they will already be families with from other parts of Blender.

Description: With this option you could select UV's based on characteristics of the mesh, eg:

Material
Face Area
UV Area
Polygon Sides
Pinned State
... possibly other options too, note that a subset of these can be accepted for the initial patch.

See mesh edit-mode, Select Grouped (Shift-G).

Challenges: adding key binding, operator and evaluating/comparing mesh data.

Changed status to: 'Open'

Added subscriber: @ideasman42

Added subscriber: @michaelknubben

Added subscriber: @tcorwine

Added subscriber: @karthik24iyer

Removed subscriber: @karthik24iyer

Added subscriber: @Nilkel

Added subscriber: @shobit30

Is this task completed?
I would like to try this.

Added subscriber: @Muchomor

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Added subscriber: @CarlosRafaeldeOliveiraCarneiro

Added subscriber: @Loading_M

Added subscriber: @matc

Added subscriber: @KalyanS

What's the status on this? Can I try it?

Yes (no need to ask, any open quick-hack is a candidate to try).

Cool, thanks! I have used blender for a while and know C++, but I am new to blender development - any pointers on how to do this? Mostly I am having trouble navigating the rather large codebase, so any advice would be greatly appreciated.

See https://wiki.blender.org/wiki/Developer_Intro/Advice

I had worked on this a couple of weeks ago. I updated my version to current master (D4792).

@ideasman42 Could you have a look at D4792 to determine whether this approach could serve @KalyanS as a basis?

@matc Thanks for the diff, I'll take a look at it when I have time and try to implement this task.

Quick question - where does the 2.8 codebase store keymaps? I've looked at some old diffs but they seem to be outdated. There's some code regarding window managers and keymaps, but where can I define custom keymaps for a space/editor?

Keymaps appear to be in release/scripts/presets/keyconfig/keymap_data/.

I don't think you do have to change any key bindings. I usually just use the operator search menu (Space or F3) to run an operator.

Ahh finally I have some time to work on this! I've implemented @matc's patch (D4792) as well as adding the Shift-G keybind for consistency (turned out to be very simple once I figured out how the keymaps worked). Unfortunately, I don't have enough Blender internal/general knowledge to know the inner workings of kdtrees, gsets, etc... does anyone have any pointers on how to extend D4792 to edge and vertex select?

I don't like asking for step by step guidance like this - I'm sure others have work to do, but I really have no idea how to go about anything in this multi-million line codebase.

Gset is just the equivalent to a set in C++ or Java. You can find the implementation in BLI_ghash.c by looking for the BLI_gset_ prefix.

From wikipedia: "In computer science, a k-d tree (short for k-dimensional tree) is a space-partitioning data structure for organizing points in a k-dimensional space."
The implementation of kdtree is in kdtree_impl.h.

I don't think you have to worry all that much about those. In each case you will just be using for example the length of an edge measured in uv space instead of mesh space. The collections should not need to be changed.

Essentially all functions in D4792 exist for vertices and edges too. Their names should be the same with "face" replaced by "vert" or "edge".

As a start I suggest to modify similar_edge_select_exec to optionally make the selection in uv editor instead of the viewport.
Basically make the following code work with edges.

        if (select) {
          if (selection_mode == SIM_DATA_MODE_MESH) {
            BM_face_select_set(bm, face, true);
          }
          else {
            uvedit_face_select_enable(scene, em, face, true, cd_loop_uv_offset);
          }
          changed = true;
        }

Ok I have a preliminary diff working on edge direction and length select (see D5108). It adds on to @matc's D4792. I would love to get feedback on this diff!

Added subscriber: @Ashwin_Ginoria

Hello, I'm Ashwin Ginoria a Student of B.Tech (2nd year) Computer Science Engineering, IIT Mandi, India. I'm new to open source Development and would love to join the comunity and I'd like to work on this task so ...
Is this task Completed ?
Also is it a beginner friendly task ?
It would be my first contribution to blender.

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Added subscriber: @Chris_Blackbourn

Fix pending review : D15164

This issue was referenced by 1154b45526

Changed status from 'Confirmed' to: 'Resolved'

Added subscriber: @DanielBystedt

@Chris_Blackbourn asked me to give feedback on this task via blender.chat.

One more useful addition to "select similar" in the uv editor would be the same as "select similar - face regions" in the 3d view. Based on a current uv island selection, the operator would select any other uv island with the same vertex/face count. You can have a look at my image example below.

One could argue that it could be interesting to add checks for rotation etc and compare uv islands in a more complex way, but I feel that just counting the faces per uv island will work just fine in most cases.

This issue was referenced by a581460728

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'Select Similar' for the UV Editor #47437