topic export single surfaces objects in Parametric design

export single surfaces objects

Nic Tulban — Thu, 11 May 2023 09:08:08 GMT

Hello
It's about MORPHs. I just inserted a surface MORPH created in Archicad in Grasshopper, I deconstructed it and tried to use it - as a support for a set of objects. But it comes not as a single surface, it is a random succesion of faces. Has anybody a solution to join these planar faces into a single surface?
Or has anybody an idea to send a single surface object through this connection?
Thank you,
Nic

Re: export single surfaces objects

Laszlo Nagy — Fri, 09 Nov 2018 16:01:23 GMT

Could you show a screenshot of how the Morph looks and how it behaves in Grasshopper/Rhino after deconstruction?

Re: EXPORT SINGLE SURFACES OBJECTS!!!

Laszlo Nagy — Mon, 27 Jan 2020 08:42:11 GMT

Does this clip help?:

Re: export single surfaces objects

leceta — Thu, 30 Jan 2020 09:41:43 GMT

you need to "join" them. You can join them as it is i.e. a bunch of nurb surfaces (you will end up with a brep) or you can convert first each nurb surface into a mesh, and the join them together as a mesh. This is up to you, and depends on what are you planning to do with the resulting "surface".

Re: export single surfaces objects

leceta — Thu, 30 Jan 2020 09:48:00 GMT

Maybe you will be interested in any tutorial on basic differences between meshes and NURBS:

Re: export single surfaces objects

leceta — Thu, 30 Jan 2020 15:13:22 GMT

as Laszlo said, It will help some screenshots, at least one of your morph object and other of you deconstruct component output.

Re: export single surfaces objects

furtonb — Tue, 04 Feb 2020 12:55:27 GMT

It's quite common though. When you create some n-gons (after moving inserted edges, for example), the topology changes in Grasshopper from clean to messy. In ARCHICAD, you won't see the inner edges, but Grasshopper will show them to you.

The attached script deals with this problem in the following way: it finds coplanar* faces based on their normal, sorts them accordingly, merges the outlines, then a boundary surface is created for each n-gon.

If the morph is completely clean, just use the original output of the ARCHICAD Morph reference component.

Re: export single surfaces objects

leceta — Tue, 04 Feb 2020 18:42:11 GMT

If I have understood ok, your script is a function already implemented in GH. Is "merge faces": it merges all coplanar faces of a brep.

This usually gives a visually clean BREP, but if one wants to further "work" with the brep (i.e, it's topology) UV directions are potentially key, and this method function gives apparently random UV directions.

A priori I prefer to work with meshes and reserve breps if I "really" need them. Brep's are luxurious data structures...

Re: export single surfaces objects

furtonb — Wed, 05 Feb 2020 06:31:50 GMT

Yes, you are right. I've had issues with merge faces for some reason (certain polys were omitted), that's why I went through the process myself, the only thing I considered a plus there is the threshold for coplanarity, which resolved this problem (I assumed it was caused by inner vertices being pushed-pulled randomly, via eye balling, resulting not perfectly coplanar surfaces). If I recall properly, the merge faces component has only one input, and spits out the cleaned brep with some numbers (before/after face count).

The posted script was a part of a larger one with a different purpose, the remainder of the algorithm required a more managable brep input than the one from the initial GS node. Maybe I misunderstood the initial question, and it won't be a solution, but it could be helpful.