Mixed-reality sandbox · Meta Quest 3 (Quest 2 in black and white)
Goldberg puts a Rube Goldberg kit on your real desk. Ramps, dominoes, planks and balls sit on the actual furniture in your room, and you build with your hands: pinch a part to pick it up, set it down, tap Run, and watch the ball roll off the desk edge and set off a chain of dominoes. Then add gears, glue and cables and it gets complicated quickly.
Open Goldberg (or the blue portal in the VR lobby)
Building on real furniture
The Quest knows the shape of your room: the surfaces you set up in its space setup, and on a Quest 3 a scanned mesh of everything. Goldberg turns those into solid surfaces for the physics, so a ball dropped over your desk lands on your desk. When the headset doesn’t know about a table, you can mark one by pinching three of its corners.
Building happens in a frozen “build mode” where nothing falls over while you work. Parts snap upright when they’re nearly upright, and pressing Run hands the whole layout to the Rapier physics engine. Stop puts everything back where it was. Parts that roll away can be pulled back by pointing at them and pinching.
Gears that actually mesh
Gears were the hard part. Simulating real gear teeth colliding is slow and jams constantly, so the teeth are drawn but the coupling is maths: two gears on parallel axles, in the same plane and the right distance apart, are locked so their surface speeds match. Every gear has its own tooth count and size, and they only mesh when the tooth sizes match, like real gears. A 10-tooth gear drives a 30-tooth one at exactly a third of the speed.
Getting them to look right took a few rounds. Drop a gear near another and it snaps into mesh at the right distance and turns so its teeth sit in the other’s gaps. A test measures the overlap of the tooth outlines to make sure. Locking speeds alone wasn’t enough: under load the gears slowly drifted until the teeth passed through each other, so the angles are locked too, and a gear train that jams stalls its motor instead of grinding through.
Glue, beams, weights and cables
Tap any part for a small properties panel. Glue joins parts into one rigid object: a plank glued to a gear becomes a lever arm. Beams come in any length, blocks can be made lighter or heavier, and a loose cup can sit on a lever as a catapult. Cables are real ropes strung between any two points, and while the machine runs you can pinch a cable to cut it and drop whatever was hanging from it.