3D Finger Paint

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  thumbnail

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  AR walk around and look

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  draw your favourite object around the contour!

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  the unspoken heroes

Inspiration

I didn't want to do another AI wrapper.

Sometimes I just want to 3D print whatever is in my hands. Or draw something 3D. And then print my imagination without the SOLIDWORKS/AUTOCAD grind.

What it does

Draw in mid-air with your finger. Two webcams triangulate your fingertip in 3D. See it live on your iPhone in AR. Export to USDZ for sharing or 3D printing.

How we built it

Python + OpenCV for stereo vision. MediaPipe for hand tracking. ArUco marker to anchor the world origin. Swift + ARKit to render strokes on iPhone. WebSocket to stream points in real-time.

Challenges we ran into

Meta glasses were too inaccurate. Had to pivot. Ceiling-mounted camera was impractical. Calibration is brutal. Millimeters matter. Jitter and instability made drawings look like earthquakes. Spent hours fighting coordinate system mismatches between Mac and iPhone.

Accomplishments that we're proud of

It works! Wave your finger, see a 3D stroke. No headset, no gloves, no special hardware. Just two webcams and your hand.

What we learned

You can build a 3D world from 2D cameras. Stereo geometry is simple in theory, painful in practice. Good calibration is everything.

What's next for 3D Finger Paint

Shape recognition, detect when you're drawing a circle or rectangle and snap to clean geometry. Makes exports actually 3D-printable.

Built With

• arkit
• mediapipe
• numpy
• opencv
• python
• scenekit
• swift