On postprocessing triply periodic minimal surfaces


I am new to grasshopper and rhino, hope I am not making a fool of myself by asking this.

Some time ago I found a script to generate triply periodic minimal surfaces. It is great, I really like it.

Can you please advice on how do you normally go from a generated mesh to a solid object that can be handled later by other programs e.g. CFD.

That is, how can you take this mesh and generate something like a STL or step or iges or some other CAD format. Thus far, I have only found ‘meshtonurbs’ which usually derive in a bitter and nightmarish postprocessing experience. Problems with self intersections or naked edges or non conformal meshes spur everywhere.

I suspect that in the GH file attached you’ll find lots of things that are redundant or unnecessary, the key here is how do I go from here to 3 solids:

  • The TPMS with a thickness
  • And two fluid volumes separated by the TPMS

Thanks for looking at this.

All the best,


GyroidRev32.gh (93.2 KB)

Hi there,
To emphasize the point on my previous note
Here is a picture that shows some of the problems I am running into:

Here for instance I get all these naked edges because I have a situation where the two meshes are trying to intersect and join the surfaces that connect them.
Rhino nor grasshopper will allow me to join and weld the mesh nor create a solid of these. I do not understand why :frowning:
Thanks again,

All the Srf components in your GH file are empty. You can make them pick up the surfaces from Rhino by selecting the Internalize Data option.

If the end result you are seeking looks like this


I can help you. If not, maybe someone else can.

Hi Birk,
Thanks so much for replying.
I have used the internalize data option on the surfaces that were missing.
In this file I have to use the rhino surface split option because for some reason the GH split works differently and quite simply does not do the job.
Regardless the end results should look something like this:

My plan is to use the grey part as a solid object and the green and red parts as flows in a CFD program.
The problem is that the CFD complains if there are naked edges or surfaces that are intersecting. In other words the surfaces between these three volumes should lie match well. At present the volumes are not only not closed ‘solids’ but they also do not aligning well
Can you help? can anyone help?

Sorry I meant to put this other picture in my previous post -sorry I just woke up :~