Creating a surface from perpendicular NURBS

Hi,

I got an issue creating a surface from 4 NURBS. In theory I want to join two loft surfaces as can be seen in the second and third pictures, but when I got help at my University they told me that approach might not be possible. The two surfaces should form a type of sphere where they meet in the middle and also be joined on two edges as seen in the first sketch.

I also tried to use swepe to create the roof structure in one go, but that didn't turn out very well either. Is there a way to trim and patch surfaces and then join them as a single surface that is 'accepted' by GH?

Ideally I want to control a single NURB from a set of points to create my surface. The idea is to create a parametric spaceframe (to support my structural analysis/optimazation in GSA) from that surface as done in this video: https://www.youtube.com/watch?v=SreXlycGBnM

I would be really thankful for any input!

Regards
Arvid

Attachments:

Spaceframe.gh, 19 KB

Replies to This Discussion

Permalink Reply by Riccardo Majewski on March 7, 2016 at 5:50am

Hi Arvid,

With single curvature surfaces it would be impossible to do it, as you said.

Can this be a solution?

I just found out I'm not able to recreeate a surface like a blend in rhino where 1 point is in common of the 2 edges....

Hope someone fix it :P

Bye!

Riccardo

Attachments:

Spaceframe_V2.gh, 30 KB

Permalink Reply by Arvid Brandt on March 7, 2016 at 8:22am

Thanks for your reply Riccardo!

I realised that my intention to keep the loft surfaces straight except for the intersecting part might be impossible? I would need a straight edge for the ground atleast, but I guess I could arrange that in GSA afterwards.

However, when I add my spaceframe template to the file, the real problem emerges. I need a single joined surface (not a breep unfortunately) to make it work. As seen in the picture, only one of the surfaces creates a spaceframe. Would it be possible to join a number of Breeps to make a single surface that would work in my current model? If so, I guess I could just "patch" the two missing corners to make it work?

Also, does anyone know why grasshopper put the "truss boxes" more tight in the concave part compared to the concave? I thought that would be sorted through local (U,V) coordinates..

Regards

Arvid

Attachments:

Spaceframe_V2.1.gh, 33 KB

Permalink Reply by Arvid Brandt on March 8, 2016 at 3:21am

So I decided to change my design a bit. I was able to produce a good surface by using 'Patch' and then trim (split) it. Only problem is that GH keeps referering to the orginal patched surface. I haven't figured out why GH won't use the new surface. It feels like a very simple problem, but I have been stuck on it for the whole morning so far...