Trimming cyclinders

I’m trying to trim 2 intersecting cylinders to get a 90 degree bend.
When I try this I get some strange shapes.

Pictures are attached.

Any suggestion?


Split, Delete the parts you don’t want, Join the remaining parts.

Deleting the parts you don’t want may be easier if you are in Wireframe.

Can you give some more steps please, David?
A bit of a beginner to Rhino!

  1. Use the Split command to split each cylinder with the other cylinder.

  2. Delete the parts which are not desired using the Delete key or the Delete command

  3. Use the Join command to join the remaining parts.

You may find it helpful to go through the Rhino User’s Manual, which is a tutorial, and the Level 1 and Level 2 Training Manuals.

Another method:

  1. Set the active layer to a different layer than the cylinders.

  2. Intersect the two cylinders.

  3. Use the appropriate intersection curves to Trim the cylinders to the desired shapes.

  4. Join the remaining parts.

Do the cylinders need to be intersecting at 4 points to use the split command?
Using this method produces some part results like this…3

That is the expected result from the split command. Switch to Wireframe mode to see the internal parts.

If these are solids (i.e.: join the end caps to the cylinders so that the properties window reports them as “closed polysurfaces”), then another approach would be to use “boolean 2 objects” ( I think thats what it’s called - near the bottom of the solids menu pulldown). This command allows you to click through all the possible boolean results for the selected objects so you can pick the one you want. I’m assuming you are using Rhino 6.

I don’t think there is a simple Boolean operation that will result in the mitered corner which is what I understand Rhys wants.

What will work is:

  1. BooleanSplit both cylinders using both cylinders as the cutting objects.

  2. Delete the unwanted parts include one of the two “corners” which are what Rhys showed in the first post. The remaining parts should be two trimmed cylinders and one “corner”.

  3. BooleanUnion the remaining 3 parts.

Oh, OK. I thought he wanted something more complicated than that. I surely understand the universal desire for one single “do-it” button, but my antiquated approach would be to place a vertical plane that defines the intersection and use it to trim off the cylinders, then throw the plane away and join the trimmed cylinders.