Metric to Imperial Robot Unit Conversion

[shuvachy]

Hi,

Can you please help me convert the robot system to operate in the imperial Rhino Unit system? How can we convert the system's preset metric units for robot and tool integration?

Thank you

Shuva

[visose]

Hi @shuvachy, this is a reply generated by ChatGPT:

Robots is unit-agnostic at the Rhino document level, but the plugin’s motion/target pipeline assumes millimeters for all numeric inputs and outputs (planes, positions, speeds, accelerations, etc.). The safe pattern is:

• Model however you want (imperial).
• Convert to mm immediately before feeding anything into Targets (and any other Robots components that take geometric/numeric motion inputs).
• Convert back to imperial immediately after Simulate/Kinematics outputs.

Practical Grasshopper approach (imperial -> mm -> imperial):

• Before Targets

  • Planes/points/vectors: scale geometry by 25.4 (in->mm) or 304.8 (ft->mm).
  • Speeds/accels: multiply by the same factor (in/s -> mm/s uses *25.4, ft/s -> mm/s uses *304.8).
  • Anything expressed as distance (TCP offsets, approach distances, etc.): same scaling.

• After Simulate/Kinematics

  • Meshes/geometry/planes: scale by the inverse (/25.4 or /304.8) to get back to imperial.
  • Any reported speeds/distances: inverse scaling as well.

Notes that avoid common mistakes:

• Scaling a Plane in GH typically means scaling its origin point; the axes are unitless directions. If you have plane origins separately, scale origins, then reconstruct planes with the original X/Y axes.
• Do the conversion at the boundary: keep your upstream definition purely imperial, and wrap Robots in a small “mm adapter” group so it’s hard to accidentally feed mixed units.
• If you use multiple Robots components (Targets, Tool, Frames, Kinematics, etc.), keep all values inside that “adapter” in mm consistently.