Using a sheet knife to cut an object


Hello best SU helpers. This question only for info and training.

I am using a sheet of knife to cut objects in this case a ball with a hole (part of kendama toy).
In this example the division is on a circelsigment is therefore not really on the half of the ball.
I know I can run 180 degrees with FollowMe but other object with curves have a problem…
Q Kendama.skp (2.3 MB)
Regards Albert



A few pointers…

  • Make your circle path with a logical number of segments.
    Using 96 would be better than 100 etc.
    Also easier to model about the origin/axes…

  • Rotate the circle [path] about its center so that the face you are extruding with FollowMe is located above the center of one of the segments.
    Then cut the circle-path in half by drawing a line as the diameter from the center of that segment to the segment’s center of the opposite side of the circle [axially is easiest].
    That way you now have a 180° path.
    That way the extrusion starts perpendicular to the path.
    As you have it currently it starts at the start of a segment not its center, so the extrusion is ‘skewed’.

  • Always ensure that the face to extrude and path line properly up, so that the extrusion starts perpendicular to the start of the path…



Indeed 96 works better. But it goes wrong with half a ball or a part.
training ball or part.skp (1.6 MB)



training ball or part.skp (2.1 MB)



Just repeating what @TIG has already mentioned, rotate the path by half a segment so the profile is perpendicular to the last first and last segments of the path.
Then use the curve as the path not the face.
You could also turn on hidden geometry a delete the parts of the sphere you don’t want.