Boolean Split Tool Failure

[Kim29 (Kim)]

I have 3 very similar objects created by sweeping the same section on 3 different cubes. I am unable to Boolean them, even though they do not appear to have any problems. The middle example I used the Trim tool to break them down but this created many naked edges which I have no idea how to repair. The third example, I exported to Form Z and Boolean Split in Form Z then used the Boolean Union tool in FZ, it all worked fine. I exported and imported the object to Rhino. It appears to be a lot cleaner and is a closed solid poly surface. Is there anyway to use the Rhino Boolean tools without going to Form Z?

Many thanks.

[Arda_Eren_Demir]

Any images about you’re example?

[Tom_P]

please upload a 3dm file - just drag and drop it to the Text / Post - Edit section where you can edit your post or reply…

[Kim29 (Kim)]

2026-03-10 Testing Boolean Split.3dm (1.9 MB)

My apologies forgot the file.

Also working on Rhino 8 on Mac

[Tom_P]

rhino dose not like those intense, coplanar faces for boolean operations.

will those profiles always bend in one plane ?

_intersect
both profiles (red curves)
_polyline (with project) (cyan curve) from point-snap to point snap on red curves
_trim in planar / orthogonal view

_join
_mergeAllCoplanarFaces

please note, that the sections / cuts are not 100% planar

the cyan polylines are not straight !

hope this helps - kind regards - tom

[Kim29 (Kim)]

Thanks Tom for your help. All these profile bend on the same plane. I am not sure I understand your process. If I am correct I need to do the following:

1. use intersect tool to generate the red curves

2. snap a curve to points of red curves

3. trim in ortho view

4. join

5. merge all coplanar faces

I will give this a bash tomorrow morning, thanks for your help.

[Tom_P]

yes that s what i did and it worked

[Kim29 (Kim)]

Hi Tom,

Followed your advice and it worked easier than I thought it would.
Many thanks.