A Robot Arm That Follows Your Cursor

Move your cursor across the arm above and the wrist chases it. Click and it waves. I wanted something on my homepage that reacted to you instead of just sitting there, and a real industrial arm felt more fun than another floating blob.

The model is an actual KUKA arm, pulled from an old library of robot files that roboticists use for simulation. That mattered to me: not a stylized toy, but the orange six-axis arm you picture when someone says "robot." The catch is that these files are a decade old and were never meant for a browser, so getting one to load and behave took more coaxing than dropping in a normal 3D asset.

The interesting part was making it reach. Anyone can spin a model around. I wanted the tip of the arm to actually point at your cursor, which means solving, every frame, what angle each joint should sit at so the hand lands where you are. That is inverse kinematics, and it is the same idea a real arm uses to put its tool on a weld seam. Mine is a lightweight version of it, running quietly behind a homepage.

A few choices shaped how it feels. It follows rather than letting you drag the camera, because following reads as alive and dragging reads as a viewer. It always treats your cursor as if you are standing in front of it, so it never twists around to grab at its own back. And the wave starts and ends wherever the arm happens to be, so a click never yanks it to some fixed pose.

It is an ornament, and it has an ornament's limits. There is no real physics, the arm can only bend as far as the original robot allows, and the whole thing is tuned to look right against a light background. None of that matters for what it is: a small, slightly absurd thing to play with for a second before you scroll down to the actual work.

If you want to poke at the internals, there is a tiny toggle in the corner of the canvas that opens a panel for the joints and materials. I left it in because it is half the fun.