Split surface issues

i split a surface and deleted half of it. when i show the control points the other points are still present ? this is messing me up when I subdivide the surface in grasshopper? How can I purge these other points? THanks

ShrinkTrimmedSrfToEdge thats the command your looking for.
I think…

your awesome! so many commands! who can know them all!!! thanks again!

No problem. Good luck :slight_smile:

Hi Ethank,

Years beck every now and then I spend some time browsing through the list of commands:

It’s a good (be it nerdy) way to familiarize yourself with all crevasses in the Rhino skin.


Years back - I think it was still the case in V4 - Split>By Isocurve automatically shrunk the surfaces after splitting. Some people didn’t want that to happen automatically, so a command-line switch was added to V5. You can change this switch during the command, check the command line.

Unfortunately, this option isn’t currently “sticky” in V5, so you need to program a macro to automatically do so every time, otherwise it always reverts to shrink=no…


Note that shrinking to the edge can in certain circumstances lead to problems downstream (when exported to other applications, for example) and as such, the regular shrink is often recommended. Exactly which you use is up to you but you have to be conscious of the choice.

Right- probably the better command to use is ShrinkTrimmedSrf - if the surface is trimmed on an isocurve this will shrink to the edge, otherwise it leaves a small margin, which is usually just as well to have on an arbitrary trim that is subject to file tolerance.


In my case I have still a problem with that. I splited the surface with a curve. After that, I wanted to shrink control points aound the surface. But I couldn’t shrink them. I tried to solve this problem using ShrinkTrimmedSrfToEdge even though. How can I do that ?
436-2-질문.3dm (2.2 MB)

That is the expected result- shrinking will only remove all of the extra control points if the trim is an isocurve. Arbitrary trims will always leave some points, since the full grid of points must be maintained in each direction throughout the underlying surface.