Exporting rhino3dm.File3dm to STL in python

Rhino Developer compute.rhino3d
,
1

Hello everyone,

I’m using rhino.compute to calculate a mesh.

How could I convert the 3dm decoded mesh to an STL file?

Currently I can only save it as a 3dm:

import compute_rhino3d.Grasshopper as gh
import rhino3dm

output = gh.EvaluateDefinition(definition_path, trees)
mesh = output['values'][0]['InnerTree']['{0}'][0]["data"]

mesh = rhino3dm.CommonObject.Decode(json.loads(mesh))
doc = rhino3dm.File3dm()
doc.Objects.AddMesh(mesh)
doc.Write("model.3dm", version=1)

Thank you very much!

2

Hi @Mario_Quintana Do any of the methods mentioned in this thread help you? Python script to export STLs - #2 by Willem

3

Hello Andy, Thank you for your answer.
I’m running my script in a docker container in a lambda function.
I don’t think I can start the Rhino service in order to send commands to it.
Could I do the same using rhino compute?

4

If you are already using Rhino.Compute, you could convert your 3dm to stl in your gh definition. You’d probably need to save it to disk, encode it as a base 64 string, and have that be a string output to your gh definition. We don’t have an example that does this, but I can cook something up in the next few days.

5

Great idea!

I implemented your suggestion using the Pancake export to stl component.
It’s working just fine!

This is the implementation:

Grasshoper definition:
stl_exporter.gh (9.8 KB)

Python Decoding:

import compute_rhino3d.Grasshopper as gh
import rhino3dm

output = gh.EvaluateDefinition(definition_path, trees)
stl_b64_mesh = output['values'][0]['InnerTree']['{0}'][0]["data"]

decoded_bytes = base64.b64decode(stl_b64_mesh)

with open(output_path_stl, "wb") as f:
    f.write(decoded_bytes)

Thank you very much Luis and Andy!

3 Likes