Cannot Split Surface


I am making my first Rhino model and I am trying to use my linework to split surfaces into independent shapes. When I select all the linework and use the split command, it says “Split failed, objects may not intersect or intersections may not split surface.”

When zooming around the model, everything appears to be planar and the lines are snapped to each other. No shapes were split as a result of the command. What does this mean? I used lines, polylines, curve (interpolate points) and arc (start, end, point on arc) to draft my linework.

Results of the split command are dependent on the view that is active when you complete the command.

See the note in the help for the split command here: