topic Re: Surface/Mesh from polylines in AutoCAD Forum

Surface/Mesh from polylines

novais — Fri, 11 Sep 2020 13:49:09 GMT

Hello, i have in the example attached, 10 polylines with 2m increment in Z and a surface that i've created some years ago with those polylines. The problem is, for some reason i've completly forgotten how i achieved that result wich consists in a rather simple surface composed by triangles. I'm pretty sure that i've used a mesh to do it, but now, i'm struggling to do it. Even if i loft it with the ruled option, it doesn't create those simple triangles...

Can anybody help me with this?

Thank you all.

Nuno

Re: Surface/Mesh from polylines

leeminardi — Fri, 11 Sep 2020 14:23:43 GMT

What is your final goal for the file and why do you want triangles?

TINs (Triangulated Irregular Networks) are often used to define terrain in civil and architectural applications. Autodesk's Civil 3D has features for creating TINs from contour lines.

Re: Surface/Mesh from polylines

Patchy — Fri, 11 Sep 2020 14:41:09 GMT

Plain Autocad you can use Triangulation

Re: Surface/Mesh from polylines

leeminardi — Fri, 11 Sep 2020 15:13:36 GMT

@Patchy I am using plain AutoCAD 2019 and cannot find the ribbon and the triangulate function. What ribbon is that in your screenshot and what is the direct AutoCAD command to bring up the dialog box you show?

Thank you,

Lee

Re: Surface/Mesh from polylines

Patchy — Fri, 11 Sep 2020 15:27:45 GMT

I saw it here, it shows plain Autocad. I don't have other than 2008.

https://www.youtube.com/watch?v=-yp5LXTi-84

Re: Surface/Mesh from polylines

R_Tweed — Fri, 11 Sep 2020 15:34:25 GMT

This screen shot shows that promine essentials has been installed.

Re: Surface/Mesh from polylines

Patchy — Fri, 11 Sep 2020 15:37:03 GMT

How about this one?

https://knowledge.autodesk.com/support/autocad/learn-explore/caas/screencast/Main/Details/6f038979-5e4a-4852-8007-ac63fdc22fbf.html

Re: Surface/Mesh from polylines

R_Tweed — Fri, 11 Sep 2020 15:52:27 GMT

Create your mesh and then use the meshoptions command which will bring up the mesh tessellation option dialog box. There is a mesh type pulldown to the right of mesh type.

Re: Surface/Mesh from polylines

leeminardi — Fri, 11 Sep 2020 15:57:37 GMT

I got the following:

Re: Surface/Mesh from polylines

R_Tweed — Fri, 11 Sep 2020 16:04:26 GMT

Looks like we overlapped in our responses. Interesting that meshoptions is not on the ribbon. This is a good example that not everything is available through the menus. It's just good practice to learn the commands and options.

Re: Surface/Mesh from polylines

novais — Fri, 11 Sep 2020 19:19:57 GMT

Thank you for the tip!

From what see from your picture, it seems that the mesh creates 4 triangles in the same space that in my surface only creates 2 triangles.

Is it possible to tweak the options to do it creating only 2 triangles?

Thanks!

Re: Surface/Mesh from polylines

R_Tweed — Fri, 11 Sep 2020 21:38:31 GMT

The file opens in 2013 format and the object is a surface not a surface (loft). I was able to get a very simliar result setting surftab1 to the 100 and use rulesurf, then convert the resulting mesh into a surface which gives you that distinctive look. Once you have converted the meshes to surfaces you can then union each row into one surface. The small division that you see is from the isoline setting of 6 in both directions.