create "polygon" mesh

RE: create "polygon" mesh

Don H. Fu — Wed, 18 Jan 2017 16:10:49 GMT

Under Mesh Modeling task, I see a tool called "Place Grid Mesh" - that should create a quad grid style.

RE: create "polygon" mesh

Michael Alestra — Wed, 18 Jan 2017 15:02:28 GMT

this is the issue that im having. Using Autocad poses the same problems. The analysis software uses this legacy format that the current softwares wont easily export or convert to.

RE: create "polygon" mesh

Don H. Fu — Wed, 18 Jan 2017 14:58:59 GMT

Assuming you use V8i, Mesh Modeling->Convert From Element is the tool that converts your existing solid to mesh...but you may not get quad grid by default (based on the information you provided that you did not get polygon mesh in DXF). You may need some help on mesh tools to get the style you want.

RE: create "polygon" mesh

Don H. Fu — Wed, 18 Jan 2017 14:53:52 GMT

I was actually hoping someone else who knows mesh tools to chime in...

RE: create "polygon" mesh

Michael Alestra — Wed, 18 Jan 2017 14:50:00 GMT

ok, so how do i create or convert solids or meshes to a quad grid?

RE: create "polygon" mesh

Don H. Fu — Wed, 18 Jan 2017 14:47:05 GMT

If you can create a 6x3 3D mesh in "quad grid" style in MicroStation, then yes - your DXF file will have what you want.

RE: create "polygon" mesh

Michael Alestra — Wed, 18 Jan 2017 14:14:57 GMT

i ultimately need to create the equivalent of a 6x3 3D mesh in autocad. Can microstation do this?

RE: create "polygon" mesh

Michael Alestra — Wed, 18 Jan 2017 12:54:30 GMT

I get "indexed face loops". if i create a solid cube, convert it to a mesh, i get "indexed face loops" as well. How do you make a quad grid?

RE: create "polygon" mesh

Don H. Fu — Wed, 18 Jan 2017 12:42:41 GMT

Can you try the tool in Solids Modeling task - Mesh From Element? After you have converted one of your solid elements as a mesh element, use keyin "analyze element" to check the mesh. Under Details tab, do you get Mesh style: quad grid? If you do, this mesh will retain as a polygon mesh when saved as DXF; otherwise it will not, in which case perhaps someone who is familiar with the mesh tools may chime in and offer a workaround.

RE: create "polygon" mesh

Michael Alestra — Wed, 18 Jan 2017 12:00:11 GMT

its not a surface that i want to create. I want to take 3D solids and turn them into 3D polygon meshes, a bridge structure for example. I can only get them to become 3D polyface meshes in dxf.

Additionally .ifc, iges, step are all options as well however none of my elements import over. dxf is the only one i've had success with.

RE: create "polygon" mesh

Don H. Fu — Tue, 17 Jan 2017 17:39:49 GMT

A polyface mesh can model any type of surface, whereas a polygon mesh can only model a UV bounded surface(mostly used for developable surface). DWG/DXF save/export generally follows this rule, but if you want a full control of mesh type, your best bet is to create grid mesh to begin with, or manually convert your surface to a grid mesh prior to saving as DWG/DXF. One way to check the mesh type is via keyin "analyze element", select a mesh, and check "Type Specific Details". If it has "Mesh style: quad grid", then you will get a polygon mesh when saved to DWG.

If an FEM program only supports polygon mesh, perhaps it will convert the mesh to a surface? Otherwise a polyface mesh seems preferred as it is not limited to a developable surface and is free from a separate boundary definition. If the program attempts to build solids from surfaces, perhaps it also actually imports a solid file format such as Parasolid, ACIS, IGES, etc? If it is a BEM(Boundary Element Method), then a polyface mesh seems like a better choice. Might be worth of checking this with the vendor.