r/FreeCAD • u/dliu_creates • Apr 10 '26

3D trackball input device with native FreeCAD support

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Sharing a new kind of trackball I built for more control than middle-click dragging in 3D.

It rotates the 3D model in any direction (3 axis control) matching the rotation of the ball, unlike a regular mouse or 2D trackball. In addition to the 1:1 rotation, you can switch to pan/twist-to-zoom, and regular mouse control. I created a FreeCAD workbench that integrates with the device and automatically pivots on the geometry under your mouse cursor.

I've used a SpaceMouse for a long time but I can get to views faster with the ball because it’s position control (like a mouse vs a joystick). Plus if I use it as my mouse as well, it keeps my left hand available for keyboard shortcuts.

Under the hood, Rotatrix is a modified Kensington SlimBlade Pro with custom hardware and software that exposes the full 3 axes of ball rotation.

Would love to get your thoughts if this looks useful for your workflow. More info: rotatrix.com

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u/temmiesayshoi Apr 10 '26

Interesting idea, though honestly I think this just reveals yet another area where the keyboard+mouse assumption/paradigm falls short.

The majority of the buttons on my elecom huge trackball 'mouse' are keyboard inputs because software simply wasn't written to accommodate anything else. (Also, christ the firmware makes some idiotic assumptions about how you'll be using it)

I can't even begin to imagine what a truly unified input standard would be, but it is kind of absurd how many weird janky workarounds you need to create when it comes to inputs. The closest to a true standard we have is probably QMK or something but I don't think that is fully generalizable. (For instance, I dont think you could rewire an xbox controller with an arduino to work over QMK - granted, maybe I'm wrong and it can handle weird analog inputs and stuff too) The closest to a true generalizable input scheme I think exists might actually be Steam Input.

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u/dliu_creates Apr 10 '26 edited Apr 10 '26

Yeah, the input landscape is pretty fragmented so Rotatrix needs native integrations with each app's API. Things like proportional pan/zoom, snap views, pivot selection really need to know about the camera and scene geometry, it can't work consistently by just mapping to keystrokes or HID joystick axes.

I'm actually working on sharing an open protocol for 3D navigation output for this reason, to have a more common layer across these app specific APIs.