Simple Way to change a PolygonMesh into a smooth "Spline/Curve Mesh"


i am very new to Rhino/GH and have some problems finding functions. The software is so complex , and the tutorials also ^^.

I can create a Gyriod and bake a Mesh and then transform the mesh to “NUBR mesh” , so i can export it as an STEP file. I want so run a CFD Simulation for a research porject.

Fine. But now, there are so many corners and edges, i have way to many cells.
Reduce Polygonnumber would work wenn you habe simple geometrys, but not for a Gyroid. If i reduce to 90%, there is nothing left of a gyroid ^^.

Now my question, is there a function that can make my NubrMesh smoother and wir some kind of curved lines/splines so i can reduce the number of Mesh-elements ?

Thank you.

I believe you can turn a polysurface into mesh, then to use the command “ToSubd” to make the mesh a Sub-d surface, then command “ToNurbs” to make it a smooth nurbs surface. You can try it out.

*the “ToSubd” command is kinda hidden in Rhino 6 so it won’t pop up even when you type it in command section, just click “enter” and it will allow you to select a mesh to be transformed into Sub-d

Hey thx for the answer.

i’m not sure what i’m dooing there. i just clicked and sub-d the mesh. but it looks the same. even when i run again toNurbs

What do you mean by “NUBR mesh”?
Mesh and NURBS are diffrent.

If you need a NURBS Gyroid, you’d better make it as NURBS from scratch. Here is an example:

If i export the Gyroid without using “toNurbs” i can’t import it in ma CAD-System (inventor) to work with it (for the CFD Simulation). Thats why i allways need to “toNurbs” bevore i export.

Another question, where do i have to click to reply with “quote” ?
or do i have to enter a mini code in the typingwindow ?

Hi - you just select the part that you want to quote and hit “Quote”:

That is a ridiculous reason to turn a mesh into NURBS. The CFD simulation uses meshes ANYWAY.

at the first sight yes. But how i said, i have to create some inlets and outlets and walls to run my simualtion. and beacuse we work with inventor, i need the Nurbs to work with my Gyroid in wiventor with it.

Thank you your the YT-link. now ith more clearly for me.

now, i had downlaoded a file from an YT-Tutorial.

When i backe the geometry i dont geht immediately an Nurbs-Object, i only get a Mesh with edges and corners.
with “MeshToNubrs” i get the same edgy object, but at least i can work with it in Inventor. With a Mesh i can’t work in inventor.

Did you see the link that I’ve shared? You can directly create a Gyroid in NURBS, there is no need to create a Mesh then convert it to NURBS.

yes i saw yout link, and i also downlaoded the file.
but htere are two problems with it.

  1. i cant thicken it in inventor , so i would have to thicken it in Rhino.
  2. the form of one gyroidcell does not fit 100% if you copy/paste the geometry in a line to get a big cube with many gyroids cells in it.

so, there is a possibility to create directly a gyroid with Nurbs. so now i have to learn how to work with Rhino/GH. To much things i don’t kno about