If your Original or Pro Series Onefinity (BB Buildbotics controller) loses steps when carving tight curves, arcs, or detailed artwork, the issue almost always comes down to processing overload, not mechanics.
The Real Cause: Old Hardware + Modern Toolpaths
The BB controller runs on a Raspberry Pi 3 (released in 2015). While it was great for its time, today’s CAM software generates far more detailed files than the Pi 3 can keep up with—especially when curves contain thousands of tiny segments.
Even though G-code supports true arcs using G2/G3 commands, the BB controller does not machine arcs natively. Instead, it breaks every arc into thousands (sometimes millions) of G1 line segments, each of which must be planned individually. On dense files, the Pi 3 simply can’t process moves fast enough, which leads to:
- Shifted geometry
- Skewed circles
- Letters drifting over time
- Lost steps during detailed cuts
This is a known limitation discussed extensively by Onefinity staff on the forum.
Easy Ways to Reduce or Eliminate the Issue
Before toolpathing:
- Simplify vectors (reduce nodes, smooth curves)
- Avoid traced clipart or clean it up first
- Increase arc tolerance / curve tolerance in your CAM
- Reduce toolpath resolution for 3D work
- Slow feeds on extremely dense geometry
These steps reduce segment count and ease the load on the Pi-3-based controller.
Example of nodes in a file:
Example of file with millions of nodes:
Example of same file with few nodes:
If you frequently cut detailed artwork, 3D files, or production-level jobs, upgrading to a modern motion controller—such as the Onefinity Elite with REDLINE CNC technology—eliminates this problem entirely thanks to far faster processing and true arc handling.