Mesh Output does not look like Mesh Preview

Hello Rhino Community!

New user of Rhino here, so thank you for your patience…

I am trying to convert a loft polysurface to a mesh and the problem I am having is that preview of the mesh to be made does not match the product. More specifically, the horizontal yellow line that bisects the vertical lines does not appear in the pictures below. I have similar parts that I did this operation on and I haven’t had problems with them, but for this part I do not know the cause.

Is there a way to either add a control point exactly between all of the current control points on a polysurface or a way to maintain the horizontal border seen in the preview in the mesh?

PolySurface I want to Mesh:

How the Mesh Preview looks like:

How the Mesh product looks like:

Forget the yellow line in the center for now. It’s an isocurve.

If your sub surfaces consist of 4 corners with 4 straight sides and are planar, the meshes will consist of 4 vertices. Especially when you have Simple Planes activated. To me, this mesh looks correct.


Is there a way then, to add in the bisecting line to the loft?

Hi - please post the 3dm file.

Sorry! I just attached it. And thank you for the replies!

PolySurface_To_Mesh.3dm (106.2 KB)

Hi - you can use ExtractIsocurve on the polysurface to get this bisecting polyline. You should then be able to use the same process to create two meshes (and then join these into one) as you did for the complete mesh.

1 Like

Perfect! This was what I was looking for. Thank you very much for the help everyone!