Add page "custom drawing in 3D"

[sosasees]

Your Godot version: 4.4.beta1

Issue description: i am prototyping procedural 3D visuals, so i need to use custom drawing in 3D to create procedural 3D visuals but there is no "custom drawing in 3D" documentation page.
if there is documentation about cusom drawing in 3D, i can't find it because i can't think of another name that such documentation could have except "custom drawing in 3D"

URL to the documentation page (if already existing):
the documentation page does not exist. here are the search results which should find the page "custom drawing in 3D" but they did not

[sosasees]

i want the page "custom drawing in 3D" to be the 3D equivalent of "custom drawing in 2D":
a starting guide to script‑generated visuals in 3D, similar to what "custom drawing in 2D" teaches for 2D

[Calinou]

There is no 1:1 equivalent of the custom 2D drawing API in 3D. You need to use procedural mesh generation instead: https://docs.godotengine.org/en/latest/tutorials/3d/procedural_geometry/index.html

[tetrapod00]

There is no precise equivalent of _draw() in 3D nodes (on Node3D or GeometryInstance3D or VisualInstance3D). So the exact purpose of Custom Drawing in 2D, which is documenting the _draw() function, doesn't make sense in 3D.

Existing pages that cover similar topics to "custom drawing in 3D" would be:

• Procedural Geometry for drawing custom mesh shapes at runtime. ImmediateMesh might be the closest to an immediate drawing function.
• Animating thousands of fish for drawing a lot of things in 3D

Since the underlying features are different, a Custom drawing in 3D page could make sense as a landing/redirect page for the existing pages. But it wouldn't directly document a specific feature. We try not to include tutorial pages that don't document specific features, so I don't think we should duplicate the documentation for a specific existing feature like ArrayMesh in a new page either

[sosasees]

we could add this especially‑written message box above the normal search results for "custom drawing in 3D" on the search results page:

you might be looking for these pages:

• Procedural Geometry
• Using ImmediateMesh
• Animating thousands of fish with MultiMeshInstance3D

[tetrapod00]

We really don't have that much control over the search to do that

[sosasees]

how could we get the ability to add especially‑written messages above automatic search results?