Rebuilding a corrupt, third party imported brep, turning it into a surface (1.3 MB)

Dear all,

I want to share a Grasshopper problem with you, which I however solved but I am not happy with the surface quality, neither with the complexity of the GH-file. Maybe this could be done much easier.

I imported a test shape (knowing it was quite badly built) and made sections through it, extracted the edge curves and turned it into a surface with NetSurf (file attached above).

  • There are some problems with the section curves, sometimes they are not covering the whole brep, depending on where I position the sections. Is there a workaround?
  • Could the whole setup be more optimised, simpler?
  • Is there something I missed or is there a much better approach to this problem?

Sorry, this is a big file but yet I think the problem is super interesting.

Best regards,

I’m curious why you are using Grasshopper and not basic Rhino?

Can you upload a .3dm file with the input and final result?

I would say, because it’s more exact with Grasshopper. The 3dm file is internalised in the brep component.

How is it “more exact” with Grasshopper? There is no difference is the accuracy of the calculations.

“more exact” was perhaps not entirely correct.
I could do it in Rhinoceros but the ambition here is to create a parametric tool/method that can be reused. Also I want to choose e.g. points on curves and surfaces mathematically rather than with the mouse, which was my idea of “more exact”.
Additionally, the goal is to create a surface with perfect zebra pattern analysis. That’s a tough one.
But I’m open for a perfect surface made in this Rhinoceros anyday, so far I wasn’t happy with the results. :slight_smile:

If you want an untrimmed surface you could use something like that.

I’ve been working on a GH tool to clean up a certain type of solid geometry construction with nearly coincident surfaces where parts are not joining. I can make centreline end points precisely identical and generate new surfaces. But I cannot necessarily get clean and complete surface intersections in GH - whilst I can in Rhino.

The difference is that I can adjust the document tolerance on the fly in Rhino. By creating the surfaces with a tighter than normal tolerance and finding the intersections with a looser than normal tolerance I can achieve an intersection that fails at normal tolerance. As far as I know (and I’m a GH newbie, so let me know if I am mistaken) it isn’t possible to have different tolerances at different stages in the GH process (I know there are some components where tolerance can be input, but not many) so I cannot achieve a result in GH that I can in Rhino.