Mesh from closed polyline when it fails to make a mesh?

[Tom_Holt]

I was using mesh from closed polyline, but there are moments when it stops working.

For instance one below at the center is null and cannot be converted to mesh:

meshfromclosedpolyline.gh (4.4 KB)

What are other methods normally used to mesh closed polyline?

Adding point at center always create mesh from a closed polyline but then issue with concave/convex shapes occur.

[dale (Dale Fugier)]

Hi Tom,

Mesh.CreateFromClosedPolyline requires that the input polygon must project to a plane and the projected polygon must be a simple closed curve. My guess is the polygon that isn’t meshing doesn’t meet the projection criteria.

– Dale

[AndersDeleuran]

I usually triangulate closed non-planar polylines first, using Polyline.TriangulateClosedPolyline, and then generate a mesh from this. Works pretty well:

[Daarshini_Rajan]

Hey there, sometimes this method fails for me too. Have you ran into a similar situation? What was ur workaround in that case ?

[AndersDeleuran]

@Daarshini_Rajan

Have you ran into a similar situation?

Indeed:

Close mesh gaps

For what its worth, this appears to be some limitation of the TriangulateClosedPolyline method: [2018-10-18%2016_10_18-Grasshopper%20Python%20Script%20Editor] 181018_problemfillmeshgaps_TroubleShootAHD_'00.gh (8.9 KB) Perhaps something for the McNeelies to have a look at? Or maybe it just wasn’t designed to handle cases such as this? Either way, you probably want to weld your edges and ensure that your normals are unified and such, before running either of the suggested algorithms: [2018-1…

@Daarshini_Rajan

What was ur workaround in that case ?

Depends on the case, but here’s one:

Mesh Between 2 Sets of Points Along Curves

Ah yes, the triangulate method has been known to not always work predicatively in all cases. A simple/robust/efficient method is to generate ruling lines between the two set of points, and then mesh these (as a two-dimensional point grid), here using the components from Mesh Edit: [2019-09-26%2009_44_42-Grasshopper%20-%20190926_TriangulatePolyline_Yup] 190926_TriangulatePolyline_Yup.gh (8.5 KB)

@Daarshini_Rajan

… sometimes this method fails for me too.

If you post your case (i.e. provide files and screenshots), that might help the McNeelies troublehshoot why the method failed.

Edit: Ah you’re probably referring to the method implemented in the original post, but replied to me. Anywho, welcome

[Daarshini_Rajan]

Nope, I meant to reply to you. It failed for me because I was trying to triangulate a non planar polyline. I have not tried your workaround yet. Thank you for your prompt reply !