Not able to CONTROL POINTS after boolean


HI, not sure i am in the right place. Been trying to work on control points after a boolean of a half sphere in a plane. The two identities dont seem to be able to merge to create one single obejct that i would like to modify slightly with control points. Is there something i am missing here ? Been joining, tried to patch (results all over the place) or rebuild but the half sphere keeps the control points of the invisible part. How do i make one mesh out of those 2 objects ?
Seems like a super easy thing, but can’t seem to find any answer. Went to the entire LYNDA tutorial and tried to search exemples on youtube and google but can’t seem to find.
Thank you so much in advance for your help. R


try ShrinkTrimmedSrf

if that doesn’t work, upload the .3dm here and someone will be able to sort it out for you.

(David Cockey) #3

Which Boolean operation are you using? If it is Union or in some situations Difference the result is a polysurface and control points are not available for polysurfaces. You can explode a polysurface into individual surfaces and the control points for each individual surface will be available.


Thanks @davidcockey
Using Difference, but looking to create an organic shape like a navel with soft transition from a half sphere hole into a terrain with valleys so modifying individual parts makes it nearly impossible to obtain a fluid result ok enough to cnc on e done. I tried fillet and blend etc but cant get the control points to work afterwards either. Anyway i can convert/export those surfaces into something editable and with a manageable amount of points?
Thank you so much in advance, R


thanks a lot @jeff_hammond will try this in the morning once back on my computer!

(David Cockey) #6

Try Drape and experiment with the spacing.

How much experience do you have with Rhino?


Thanks @davidcockey
I have tried to “soft” drape before too. but hard to get the surface of the drape to recreate the exact position of the bottom of the ball.
I am trying to create a perfectly shaped pocket for a ball made of steel. The organic form will be cut in stone.
My issue is that i am trying to get a perfect bottom of a sphere with irregular sculpting job around it…

I am new to rhino, a week and a half in, “attended” entire LYNDA video course and been playing around using the super useful help panel in the software.

I tried surface network unsuccessfully, lofting unsuccessfully, patch, blend… but maybe i’m just not good enough with the settings? so far best result is by hand, one control point at a time using softeditsrf, rebuild and insertcontrolpoint, with help of Clipping planes to work in cross sections. But its hard to get the socket for the ball right, only doing an visual approximation… would be great if i’d manage to create my organic terrain (with fewer ctrlpt) around my ball and then manage to create a smooth transition between the perfect ball matching socket and the soft terrain above.
Will send original file in a bit.


here is a file in progress. I didnt do the boolean difference because it would produce a polysurface not allowing me to use control points. any advice welcome ! thank you so much for your help ! !! BH1 400x400 3rd ball deeper copy.3dm (4.5 MB)

(Pascal Golay) #9

Hmm - you might experiment with SoftMove on a fairly dense surface’s selected control points, and a sphere, using the sphere as a surface input to SoftMove.



thanks @pascal. “Sphere as surface input for softmove” sounds like exactly what i’m looking for! how do you assign a surface to softmove function ? Sounds really good !


I am on MAC rhino, and trying to do this :

but every time i click to define the offset, everything gets deselected and nothing happens… :frowning:
tried a couple times. Is there something i am missing here ?
thanks a lot !

(Pascal Golay) #12

Hi Rui - as far as I can see on the mac, it works but the preview is broken - that is, while I drag the offset, I see the selected points moving as expected but when I click, they revert in the preview. - however if I then click Done, the result is correct. So there is a bug there but I think it will work.