From Nurb to Mesh

Hi all as you can see I am trying to create a mesh from a simple grid that I’ve done with nurbs just a surface from 3-4 corner points.

I’ve been trying to figure out WHY, sometimes it is very arbitrary that when I do mesh from a nurb sometimes it will give you a horizontal line across the plane and sometimes it wont and sometimes it will give you both horizontal and vertical…It is very bugging and I really want to know why and how i can control this…

Thank you

That looks odd for a surface from corner points - the top and bottom edges don’t look straight in your image. Can you post the Rhino file with surface?

Is the object you created far from the world origin? What mesh settings did you use in the Mesh command?


Here, I’ve attached my rhino file. It is relatively simple to understand I
have this Grid that I created and I basically used surface from 3-4 corner
points for a command to get the Polysurface (nurb) then as you can see

next to it there is a mesh, for mesh I just typed in ‘mesh’ command. So as
you can see some of the quads have vertical lines, some don’t, and some
even have both vertical and horizontal. I want to know why it does this if
this is an arbitrary thing because I’ve spent about a day to figure it out,
can’t so. If there is any way to control having lines in the mesh such as
having only horizontal or only vertical or both.

Thank you,

Help.3dm (216 KB)

OK, I didn’t realize from the image that it was a series of surfaces and not just one surface.

@pascal This actually looks like a bug/failure in the Mesh engine… All the surfaces are planar and 4 sided, so checking “use simple planes” should make them all with just one mesh face… Can’t find a group of settings that work however.

I can probably throw together a script that can fix this temporarily, but that’s about all until the McNeel folk see what’s going on…

Dang, started to write the script and then realized I had already done this… Geez, too many scripts to remember…

Anyway, here is a python script that will create quad meshes from your quad surfaces. (1.2 KB)

Edit 2: Here is a different version, this will only let you select single untrimmed quad surfaces as input. (561 Bytes)


its okay! I was just very annoying why some of the planes would give me
different lines.

you think they will fix it later on?

I don’t know if this will be looked at in V5 - in fact almost certainly not, I would say. However, I will put it on the pile and hopefully when meshing gets another look, we can use this as a test case. However, it seems to me what you really want is to be able to say explicitly how many quads in each direction you’d like to see, is that correct?