Invalid Surface

Hi everyone ;

I've got a problem with my SrfSplit Component, and if some kind soul could help me, it would greatly help me.

I'm trying to split a piece of cylinder with a closed curve, to remove the interior.

But after the SrfSplit Component, even if graphically, all seems well, the surface that comes out is an Invalid Surface, and I cannot work on it anymore.

I've tried the Null Item Component to see where the error comes from, but I can't understand anything to this jargon...

Does someone have a clue ?

Thanks a lot !

Replies to This Discussion

Permalink Reply by David Rutten on June 26, 2012 at 7:24am

Hi Rhydro,

looks like a bug deep down in the splitting code. Unfortunately I do not have the time right now to dig into it. It will have to wait until I'm done with the new cluster features. Please remind me again after 0.9.0001 is released.

David Rutten

david@mcneel.com

Poprad, Slovakia

Permalink Reply by Rhydro on June 26, 2012 at 7:45am

Hi David,

Ok, thanks for the answer.

I'm going to try to circumvent the problem.

Is there a way to intersect a brep and a surface ? I mean, an other way than BBX (it was the way I obtained my closed curves I used to perform the SrfSplit)

Permalink Reply by anthony viola on July 8, 2012 at 2:56pm

Rhydro-

Did you ever figure a way to circumvent this? I am having the same issue and it seems that if I change the domain of the sub-curve that I loft to create the section of a cylinder it sometimes works and sometimes doesn't. Looking for something a little more consistent.

Anthony

Permalink Reply by Rhydro on July 9, 2012 at 5:06am

Hi Anthony

Unfortunately, I have not been able to find any magic bullet.

I used a Trim Solid Component, with a brep built from the curve I wanted to use in the SrfSplit Component. Then, a Brep Component Box can explode the result and you can choose which one of the surfaces you want to keep.

But since this method doesn't always work either, I'm doing both the SrfSplit and Trim Solid methods, and then I use a Variable Expression component, with the function [Contains(x, "Trimmed Surface")] to check the validity of my surface and to choose one of the two obtained surfaces.

With two methods, twice as likely to obtain the desired result...

Sorry I couldn't help you more.

Permalink Reply by Cheryl Lee on February 17, 2013 at 9:35pm

Hi David,

I have exactly the same error in trying to split surface. I'm using the latest GH 0.9.0014 for Rhino 4. Wondering if you have found a solution to it yet.

Thanks a lot!

Permalink Reply by Piers Morgan on May 8, 2013 at 6:15am

I had the same problem and made a kind of clumsy workaround: from the SurfaceSplit component I used a NullItem component, I Dispatched the SurfaceSplit fragments into valid and invalid surfaces, then used a SolidDifference to subtract the valid surfaces from the original surface. This gives the result I wanted from the SurfaceSplit.

Permalink Reply by Vishwadeep Deo on July 3, 2013 at 7:24pm

Here is another crummy workaround. Using "Null" + "Dispatch" components filter out invalid AND valid split surfaces. Then on the invalid surfaces, extract edges using "Deconstruct BRep" and remake the surface using "Boundary Surface". You should get a new set of valid surface that were invalid earlier. Then you may "Merge" the 2 streams (original valid surface and the new valid surfaces) to get back the desired result.

Permalink Reply by h on July 23, 2013 at 9:28pm

I have always been able to fix this problem by rebuilding the curve prior to splitting. Just rebuild with a sufficiently high number of points that its indistinguishable from the original.

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