MergeAllCoplanar fails

Hi all. I do need to generate the overall surface of this beautiful BREPs and unfortunately I can’t find the proper way to do so.

My approach it is to flatten all the surfaces to Z0 using the Peter's Tool Z-direction Flatten to 0 and after that to do a MergeAllCoplanar operation which seems to fail.

Know somebody how i can extract the overall surface of this shapes?

Best regards.

MergeAllCoplanar_fail.3dm (290.2 KB)

This is what I do need to achieve:

MergeAllCoplanar_what_I_do_need.3dm (37.4 KB)

It’s getting confused because you have multiple overlapping faces.


-_Explode flattened groups
-_Join area selected (in yellow)

-_Join all other faces in flattened output
-Run _MergeAllCoplanarFaces again

It is there a script or Grasshopper definition that can extract the overall surface of a BREP?

I do tried a few times the method you provided but I do get only bad results:

1:You can use the ‘MeshOutline’ command in top view to extract the outline of the object.

2:use the ‘PlanarSrf’ command to create a surface.

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Thank you. The MeshOutline command do the trick.

Do you know any Grasshopper way to achieve the same result? (7.0 KB)

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Thank you very much. It is possible to make this definition to wotk with BREPs instead of meshes, because the curves generated from meshes are converting all the circles and arcs into segmented polylines, unfortunately.

You can use Silhouette instead of MeshOutline, which will get you real NURBS edge curves, but you will have to clean up the internal ones by using CurveBoolean and just getting the outer border(s).

I do found the solution here: boundary region of mulitiple curves - Grasshopper (