How can I merge serfaces?

Replies to This Discussion

Permalink Reply by Giulio Piacentino on May 18, 2010 at 7:54am

Hi Jerrimo,

were you trying to make these surfaces adjacent, or tangency/curvature continuous? From the picture, I was thinking the previous, but I'd rather be sure as the answer probably changes depending on this.

- Giulio
______________
giulio@mcneel.com
McNeel Europe, Barcelona

Permalink Reply by Jerrimo on May 18, 2010 at 9:06am

hi Giulio, I want to create a continous surface that is not constituted of separate entities but rather one surface. Furthermore, this continuous surface is supposed to be a timber structure. Here some further information in the image:

Thanks

Attachments:

• Surface Problem.png, 1000 KB

Permalink Reply by Giulio Piacentino on May 18, 2010 at 11:11am

Hi again Jerrimo

I cannot see the attached file. However, the first step might be to constuct the surface in Rhino. Here some possible approaches:

• construct a single NURBS surface from grid of control points, and specify some of the control points of the grid at a different height. Then, cut the unwanted part at the bottom. You can use F10 to manipulate control points in Rhino. It could be that this method is too coarse at the level of possibilities, and does not gives you the sort of shapes you seek. You can automate "Surface from points" in Grasshopper, though.
• use many single NURBS patches. They need to be constructed continuous at the fist step, because Grasshopper does not have the MergeSurface functionality. This will prove to be difficult, but maybe Sweep1 and Sweep2 in Grasshopper 0.6.59 will help.
• see if T-splines might help. It might allow you to add different patches and "glue" them together with continuous curvature. I know that the programmers at T-splines were experimenting with a new plug-in for Grasshopper, it might be worth it to investigate. That plug-in was using meshes and smoothen them into organic (poly)surfaces.

I hope this might be of some help,

- Giulio
__________________
giulio@mcneel.com
McNeel Europe, Barcelona

Permalink Reply by Jerrimo on May 19, 2010 at 3:50am

Hey Giulio,
Thank you so much for your detailed answer. I will play around with your suggestion.
In my last replay there went something wrong with the image. Here is it again.
Thank you!!!!

Attachments:

• Surface Problem.jpg, 339 KB

Permalink Reply by trevor.patt on May 19, 2010 at 8:43am

check this thread, looks similar:
fillet merge (??) poles to freeform surface

or since you say you want a timber structure eventually possibly also:
one more push before the thesis ! (i'm a shigheru ban wannabe)

Permalink Reply by Giulio Piacentino on May 19, 2010 at 9:25am

Thank you Trevor, these were nice discussions.

- Giulio
________________
giulio@mcneel.com
McNeel Europe, Barcelona

Permalink Reply by Jerrimo on May 20, 2010 at 2:07am

Trevor and Giulio thank you so much for your help. It doesn´t seem to be a simple issue. But i will study it now.

thank you guys

Permalink Reply by Matthew Sederberg on May 21, 2010 at 3:24pm

Jerrimo,

Just looking at your structure, it seems like T-Splines might be a helpful solution to you. After you've made your file in Grasshopper, just convert your NURBS to T-Splines (the shape won't change), turn on control points, select all control points, and run the tsWeld command. Any coincident points will be welded together, and assuming your surfaces meet up with coincident points on the borders, you'll have a single c2 tspline surface, which you can convert back to nurbs.

Let me know if you have questions.

Matt