Hi DBHoward -
Please post both the 3dm file and the output from the Rhino SystemInfo command.
-wim
UkuBridgerevised.3dm (52.4 KB)
I dont know where to get the system info you requested. I am performing a sweep2 then the BooleanDifference.
Apple macOS Version 26.3 (Build 25D125) (Physical RAM: 18GB)
Mac Model Identifier: Mac15,7
Language: en-US (MacOS default)
.NET 8.0.1
A few things to help your Booleans work / work better
- Booleans work better with two solids. You have a solid and a surface
- The surface may add or subtract unexpectedly, depending on the surface normals. Use the Direction command to flip the normals to get expected behavior.
- Booleans work better when the forms OVERLAP. It is not clear if yours overlap, so just make the intersecting surface WAY bigger than it needs to be. Donât try to make it âexact,â GO BIG.
Also, I do not recommend booleans as they generate âdead endsâ in modelling. Instead, split the two forms to each other. If they intersect, they are guanteed to close and join. [Important for prototyping!] Use this process I call âSplit-Split-Tossâ:
- Split A to B
- Split B to A
- Delete the excess / remainders
- Join!
- The result is a perfectly clean form that can be joined 100% of the time.
Why does this work? You split each form to each other. There is no way to get an opening or naked edge ⌠the two splits only work if they are overlapping and defining a volume.
Is this the kind of video response youâre looking for? https://drive.google.com/file/d/14A1yWfRIA7DuUCx2jPBzK2U4CVrp6K9L/view?usp=drive_link
Nice video!
So, yes, there was not enough overlap.
I would also guess that the box has openings somewhere.
Did you try the Split-Split-Toss method?
By the way, I have a trouble-shooting tip that took years to learn:
If its quicker to rebuild from scratch than analyze and fix it, then re-build it.
Hi @DBHoward ,
Type Systeminfo in the command line interface and hit enter and then you can copy and paste the results.
Iâve been away from Rhino for a while but Iâm back! 
Iâve been using the âCut with Surfaceâ method in Solidworks for a long time, so Boolean Difference and Boolean Split feel very intuitive and functional here as well
Yes, but solids + boolean operations will leave you at a âdead end of modelingâ and limited options to edit. Youâll have to rebuild the whole thing â which wonât be very close as none of the input geometry still exists â so, not much of an edit.
If you use curves to build all of your surfaces and then split/trim them, you can ALWAYS go back a few steps for accurate edits / experiments / or re-builds.
This seems hard to explain in a post with text. I may need to do a video.
Iâm still a bit torn, to be honest! Even during the form-finding stage, if my sections and guides are already defined, I might still stick with Solidworks. Iâve just returned to Rhino after a long break and Iâm exploring if I can truly fit it back into my workflow. As you know all too well, clients ask for so many revisions that the parametric flexibility of SW is hard to give up. Weâll see how it goes!
Its in X-ray view. the saddle slot and holes for the strings are there just for reference, I specify their location in CNC software. Once I have the final shape I delete the saddle slot and holes for the strings. I tried it the other way around extruding those areas and it became a real issue for the CNC.
I
Iâve had a CNC for years but not the 3D software so I was shaping everything by hand after the CNC just cut the basic outline of the shape.
Thereâs a good reason for the âbooâ in boolean.
Well, seemingly not always. Try making this bridge with curves and trims (blue model) and with boolean split (red model):
Resulting surfaces at split face are identical.
Ability to explode objects and untrim faces is no different:
Boolean split here is just an efficient shorthand, saving the user time compared to building from curves and trims.
And, to consider the other solid booleans: Rhino now offers options to keep the input geometry and cutters. Admittedly you need to stash them if you want to keep them long term, but I think things have moved some distance along from the early days of booleans. They are tools that bring advantage if used judiciously.
Regards
Jeremy