Welcome to the Onshape forum! Ask questions and join in the discussions about everything Onshape.

First time visiting? Here are some places to start:

  1. Looking for a certain topic? Check out the categories filter or use Search (upper right).
  2. Need support? Ask a question to our Community Support category.
  3. Please submit support tickets for bugs but you can request improvements in the Product Feedback category.
  4. Be respectful, on topic and if you see a problem, Flag it.

If you would like to contact our Community Manager personally, feel free to send a private message or an email.

Fit Cylinder mesh tool custom feature

joshtargo
joshtargo Member Posts: 683 EDU
in FeatureScript

I'm sharing my FitCylinder.fs custom feature for people to try. The UI has been a lot of work, and I still don't love it, but the feature can be quite complex with all of the options.

It fits a cylinder (with or without draft) to a mesh for reverse engineering holes, bosses and shafts. It uses RANSAC to ignore outliers, then refines the fit.

image.png

Two ways to get points

  • Mesh Points: pick vertices on the mesh and it fits through them. You need at least 6 points, or 4 if the orientation is locked.
  • Radial Raycast: place an emitter cylinder (drag the triad and radius handle, or pick a vertex). It fires rays inward or outward from it and fits the hits. This works well for holes and bosses, with no point picking.

Options

  • Emitter direction: pick an entity (line, plane, circle, mate connector), or fit a plane through picked points.
  • Match emitter orientation: locks the fitted axis to the emitter axis, which is the default and the fastest option. Uncheck it to choose an orientation yourself: Auto (slow), from an entity, or from a plane fitted through points.
  • Outlier tolerance: points outside it are ignored, and the feature warns "Outliers Detected" if any were.
  • Allow draft: fits a cone instead of a straight cylinder and reports the draft angle.
  • Ray controls: ray levels, rays per level, and an optional maximum ray length.
  • Result: Extend End 1 and Extend End 2 (with drag handles), optionally move the center to a picked point, and choose a Surface or Solid output.

Computed Data: radius, height, hit and inlier counts, and RMS and max error.

Categories