It is important that geometry be well defined. Try to be familiar ahead of time with the types of toolpaths you will use, and generate geometry accordingly.
When your file is scaled, positioned, and ready for export, run the “check” command in rhino, or something similar, to make sure all geometry is valid.
If you need to generate additional geometry after you’ve begun tooling in RhinoCAM, it is possible to continue modeling in Rhino and switch back and forth fluidly.
It is helpful to organize geometry by layers. If you are doing a series of contour cuts, put interior cuts on a layer and exterior cuts on a separate layer, so that you can select them as a group and cut them in order. Keep surface milling geometry on a different layer than containment curves, etc.
Scale Rhino Geometry
Prior to tooling in RhinoCAM your geometry must be scaled to the size you want your final model to be (1:1). Units should be in inches for the router.
Sometimes scaling causes issues in Rhino. This is especially true when the original Rhino file is in large units, such as kilometers, or miles, and the final model is very small. It is helpful in this case to change units without scaling (ie. if the bounding box of the model is 14 miles on one side, make that14 inches; do not scale it to 887040 inches). Then, once the units are correct, scale the geometry up or down by the necessary factor to make it the correct size. It can also help Rhino scaling issues to set the Rhino Absolute Tolerance to 0.0001 units.
After scaling, re-”check” the geometry.
Position Rhino Geometry
It is important to make sure you position your geometry at the Rhino file world origin, not at the CPlane origin. If you moved the CPlane, be sure to reset it before positioning the geometry.