Intersect Faces to trim rafters in an overlay roof situation

Heya:) I am trying to trim rafters as they intersect an existing roof plane. I haver been able to use the Intersect Faces from the right click option on Mac. There are more options under the Edit dropdown menu, but i don’t understand the difference.

My rafter system is an amalgam of component and other group geometry. I haver tried exploding and making each rafter unique but i cannot seem to get the rafter to accept the intersect face plane lines as real geometry…

I recently reverted to 2023 Pro instead of 2025 to fix some bugs FYI.

Any easy solutions or thoughts?

Mira and Nathaniel Existing .skp (716.8 KB)

First, it appears you’ve balled up your model by exploding some of the rafter components such that they’ve merged with other geometry in the model.

I would suggest that you model a volume as a cutter to trim the rafters that need trimming. Since your rafters are components I would make the ones that need to be trimmed unique in pairs and use Trim from Bool Tools 2 or Eneroth Solid Tools to do the trimming. The example is done with Bool Tools 2.
Trim

Side note: It’s not a good idea to string your model out across the county. Keep it close to the origin.

Also make sure to stay on top of correct tag usage. ALL edges and faces should be created and remain untagged. Otherwise you’ll create problems for yourself.

And purge unused stuff periodically.