Boolean split, why doesn't it "merge" faces?

been using boolean split a lot recently. curious why is doesn’t merge faces?

here’s an example, the cutting surface is extracted from the inside wall, it is also planar. after boolean split is done the faces aren’t merged. i would think that it would merge.

also, let’s say we use a curved surface that is extracted. we get the same behavior, it doesn’t “merge” the surface. since we used a surface that encompasses the object to be split, why doesn’t it use the splitting surface to replace that “unmerged” surface?

this really isn’t that big of a deal when doing planar splits, i can just run MergeAllCoplanarFaces after the split. extra step, no biggie i guess, it’d be nice if it merged them.

the big problem i have is that if it is a curved splitting surface, i have to delete those “unmerged” surfaces, and typically MergeAllEdges and sweep the surface again. that’s the pain. and when i do this dance i usually have a bunch to do. if it was one or two a day, no big deal to do a manual “replace”. but when i’m having to rebuild and remake the a surface every 10 minutes it gets tiresome.

maybe i’m missing out on a command to do these curved surfaces?

@pascal sorry to bug, but i’m getting crickets (ha, i made a funny…bug…crickets. ok that was lame)

one logic explanation would be your mouse pointer. its yellow, that cant work. other than that can you post that file?

it was just a quick example i made. here’s the file.

don’t hate on the yellow cursor. i was elated when i found out i could change it in accessibility settings. i’ve been missing the old windows NT yellow cursor. :wink:

split example.3dm (228.2 KB)

Windows NT, something i remember from being half a child still, not that i have grown more mature since then, i probably got dumber by each decade, now i am working on a mac, a system which has become increasingly impossible to customise something which i appreciated this system so much for in the beginning. i have a humongous list of terminal hacks to make natural things like turning off the wait staits of the keyboard etc. possible. but apple is deciding each year to close more and more windows either purposely or just blatantly ignorant. in that matter i salute the customisability and the individuality. ps: never found a way to customise the mouse without having to install an app which then keeps running in the background :see_no_evil:

regarding that split, if this is something you need and use very often, macros are often used for extactly that. one could utter a wish to implement this into the commands which could benefit from such an option. regarding your curved surfaces, that might be less easy have you got an example for such?

Well, in your case maybe you can use BooleanDifference instead of BooleanSplit - it seems to work differently (no idea why). You would of course need to make a copy of the original object and verify the surface normal of the splitting surface first to make sure you get it going in the right direction. In the case of planar surfaces, MergeAllCoplanarFaces would be faster. But it might help with curved surfaces.

Wirecut with a curve or a line that corresponds with your cutting surface also seems to work better.

BooleanDiff.3dm (1.9 MB)

what the heck? BooleanDifference, a tool that a typical user would never associate with this split imo, gives a better result than a tool that is designed for this purpose? that is odd right?

the planar surfaces aren’t that big of a deal, like you said, i’ve macro’ed out a split with a merge afterwards. in my screen shots i should have modeled up something more like your example to really show the issue with curved surfaces.

wirecut has been a command that has mystified me since it came on the scene. most of the tools i’ve never touched in rhino, wirecut being one of them, i know what they do, how to use them, and when to use them. but this one, i understand what it does, but honestly have no idea what it’s “specialty” is. (after writing this i just thought maybe i could use it to notch plywood? i’m going to go try.)

seems like a bug, oversight, or by design maybe? i think i burned out my pascal tags for awhile cause he’s not replying. :frowning:

thanks mitch, i’ll keep this stuff in mind. appreciate it.

i moved back over to mac for personal use a few years ago, my last mac was a G3 and was right before i moved to NT for 3D. with a 1.2ghz dual processor and a graphics card that was more expensive than the computer and monitor. i think my sony trinitron 21" monitor was like $800?! i thought i was the man. :laughing:

it was right when they started really cracking down on kernel extensions to customize things. a lot of developers got screwed because their software was made to customize. one of my favorites was a finder extension that gave you a dual pane view. it was nicer than using a 3rd party program because it was faster and integrated. but nope, once they did the SIP thing it stopped it all.

i’ve been down the terminal hacks road and ended up tweaking so many things i don’t know what is default and what i’ve done. i tried to keep track but gave up.

i get it from a system point of view. having that much access to the OS does open potential security issues. but from a user pov, it was lame and “over reaching” but after sometime i didn’t miss them really and felt “safer”.

i actually did have my yellow cursor on my mac for a few months before the 3rd party app couldn’t function anymore. :laughing:

like you said, i wouldn’t dare install a 3rd party app on my pc to change the mouse color no matter how bad i wanted the yellow one. that’s why i was stoked i could change it in accesibility. :wink:

It surprised me too a bit. Basically this looks like a matter of what the operation decides to keep and what it decides to throw away. As the splitting surface is concurrent with some of the to-be-split-surface(s) it can decide to keep either a part of the splitting surface or part(s) of the original. Looks like it decides differently in either case, I don’t know if that can be ‘tuned up’…

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