topic Re: Element Bodies: Meshes, Tessellated meshes, Nurbs. in Archicad C++ API

Element Bodies: Meshes, Tessellated meshes, Nurbs.

drjustice — Tue, 14 Sep 2021 07:36:11 GMT

Hi!

I am looking to extract triangles out of a ModerAPI::Element.

I see 3 methods:

GetTessellatedBody/Count()
GetMeshBody/Count()
GetNurbsBody/Count()

What do these return exactly?

Does the GetTessellatedBodyCount return the number of mesh+nurbs bodies?

In other words, if my object is a nurbs, will GetTessellatedBody return a polygonal tessellated version of the nurbs geometry?

Also, I read somewhere that tessellated bodies doesn't mean triangles, it only guarantees convex polygons. is this true?

Finally, let's say my element is a wall, will getting the tessellated bodies of the wall contain the openings, or will I just get a flat rectangle?

thx!

Re: Element Bodies: Meshes, Tessellated meshes, Nurbs.

Viktor Kovacs — Mon, 07 Jun 2021 20:09:56 GMT

There are two types of bodies in the model:
- MeshBody: Body represented as planar polygon boundaries.
- NurbsBody: Body represented as a NURBS surface.

TessellatedBody is a helper class that contains the planar polygon boundary representation of the body regardless of it's original representation. So if you would like to have triangles, you can always use TessellatedBody, and don't have to use the other two types.

From a TessellatedBody you can access Polygon instances, and get ConvexPolygon instances from that polygon. A ConvexPolygon - as the name says - always convex, so you can easily triangulate it by forming a fan from the first vertex.

Re: Element Bodies: Meshes, Tessellated meshes, Nurbs.

drjustice — Tue, 08 Jun 2021 16:23:39 GMT

Thank you. That's exactly the answer I was looking for. Cookies for you.

But also, an important part of the question that remained unaswered:

"let's say my element is a wall, will getting the tessellated bodies of the wall contain the openings, or will I just get a flat rectangle?"

Re: Element Bodies: Meshes, Tessellated meshes, Nurbs.

Viktor Kovacs — Wed, 09 Jun 2021 06:59:10 GMT

The element will have all the holes. Openings will be separate elements, but their place will be cutted out from their owner element.

Re: Element Bodies: Meshes, Tessellated meshes, Nurbs.

drjustice — Sat, 19 Jun 2021 05:47:25 GMT

That is most excellent, thanks