Add plugin geometry injection API for the 3D map scene

[mohsenD98]

🚀 Description

Plugins currently have no way to draw custom geometry inside the 3D map view. This PR adds a minimal, stable API surface that lets any QField plugin inject and remove geometries from the 3D scene at runtime.

✨ How a plugin uses it

let canvas3D = iface.findItemByObjectName('mapCanvas3D')
if (!canvas3D) return  // 3D view not active

canvas3D.clearPluginGeometries()
canvas3D.addPluginGeometry(wkt, qgisProject.crs, '#FF6600')

Demo

Screencast.From.2026-06-05.22-09-00.mp4

Plugin

Example plugin qfield-3d-inject.zip
Example plugin qfield-3d-inject.zip

[qfield-fairy]

🍎 MacOS DMG universal builds

Download a MacOS DMG universal build of this PR for testing.
(Built from commit 650b46d)

📱 Android builds

Download an Android arm64 build of this PR for testing.
(Built from commit 650b46d)

Other Android architectures

• arm-neon
• x64
• x86
• all access arm64
• all access arm-neon
• all access x64
• all access x86

🪟 Windows builds

Download a Windows build of this PR for testing and for arm64.

(Built from commit 650b46d)

🐧 Linux AppImage builds

Download a Linux AppImage build of this PR for testing.
(Built from commit 650b46d)

[nirvn]

Hm, while this gets to our objective, I'm -1 on the method we employ here.

Our approach should be injecting into the repeater3D actual Quick3DGeometry items that live within the plugin and get removed when the plugin is unloaded.

That gives us dynamic geometry, colors, line width, etc.

Also, if possible (I'd hope so 😉), these 3D geometries should live on outside of an existing 3D map view, so they aren't killed when the 3D map view itself is turned off.

[mohsenD98]

Our approach should be injecting into the repeater3D actual Quick3DGeometry items that live within the plugin and get removed when the plugin is unloaded.
That gives us dynamic geometry, colors, line width, etc.

Done

Also, if possible (I'd hope so 😉), these 3D geometries should live on outside of an existing 3D map view, so they aren't killed when the 3D map view itself is turned off.

I am thinking .. :)

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Plugin updated.