Use outlines instead of boxes for selected MeshInstances in the editor

[Chaosus]

Describe the project you are working on

Godot

Describe the problem or limitation you are having in your project

Not limitation just a visual improvement.

Describe the feature / enhancement and how it helps to overcome the problem or limitation

Currently, Godot using boxes for selected meshes which I found kinda ugly:

My proposal is to change it to be like this:

Describe how your proposal will work, with code, pseudo-code, mock-ups, and/or diagrams

Through shader I guess. Of course, this should be optional. Also, there should be options to control the thickness and color of the outline in the editor settings.

If this enhancement will not be used often, can it be worked around with a few lines of script?

No.

Is there a reason why this should be core and not an add-on in the asset library?

It's rendering stuff for the editor.

[Calinou]

reduz plans to work on this sometime in the future, but feel free to look into this if anyone is knowledgeable about it.

[Darkinggq]

yeah the outline is better, but I didn't like AABB because it interferes with meshes for 3D.

[akien-mga]

We discussed this briefly in a proposal review meeting and agreed that this would be amazing, so feature wise this seems good.

We're not sure how this can be implemented in an easy way, would need input from @godotengine/rendering folks to see how this would be done and/or if it would be best waiting for having some support for stencil buffers.

[clayjohn]

Funny enough I was just thinking about this yesterday. I think reduz' original plan would be to offer a form of built in outlines using stencils.

It shouldn't be too much work to implement, but it may take a little bit of thinking about how stencils are used and if we are able to expose stencils in a user-friendly way at the same time.

[Zireael07]

IIRC there is already a PR/proposal (forgot which) for stencils

[Calinou]

IIRC there is already a PR/proposal (forgot which) for stencils

Indeed: #3373

[fire-forge]

What if an "Outline3D" node was added that adds an outline around a 3D object like what's shown in the Unreal Engine screenshot? Then the 3D editor could use it for outlining selected nodes, but it would also be really easy to add outlines in games.

[Calinou]

What if an "Outline3D" node was added that adds an outline around a 3D object like what's shown in the Unreal Engine screenshot? Then the 3D editor could use it for outlining selected nodes, but it would also be really easy to add outlines in games.

This can already be achieved with the Material Overlay property (which adds an additional pass to all materials on a given GeometryInstance3D). However, we can't override this property in the editor only, as its modified state could end up being saved in scene files.