# PropMotion

A Claude Code skill for making 3D objects move well in SwiftUI apps.

[](LICENSE)    

<p align="center"> <img src="media/skill-demo.gif" width="360" alt="PropMotion demo reel" /> </p>

## What it's for

Sometimes an app needs one 3D moment. A product spinning on a pedestal. An achievement badge that rolls in and thuds. A coin that drops when the user hits a goal. Not a game, not AR. One object that moves well.

SceneKit does all of this and sits in any SwiftUI layout, but the knowledge of how is scattered and half of it is undocumented. The docs tell you what an SCNNode is. They don't tell you that deferred shadows silently break under MSAA, or that the first frame of a fresh SCNView compiles shaders in the middle of your entrance animation. This skill is the missing manual, written for an agent.

## What you can make with it

- an object that rolls onto the screen, settles, and casts a real shadow over your plain SwiftUI background - grab it, throw it, it bounces off the edges; every impact taps the haptic engine - weight you can see: heavy things rise slow, fall fast, land with a thud and a shiver - coins raining into a pile, marbles colliding, a wheel doing a burnout with smoke - several scenes cut into one continuous clip, like the one above

All geometry from primitives in code, all motion baked keyframes with hand-rolled physics. No Unity, no Blender, no assets to license.

## How to work with it

Two different problems, two different inputs. This is how the clip above was actually made.

**Shape: show photos.** The dumbbell started as two photos of two different dumbbells,