Bad Mesh after joining Parameter Loft Meshes

Grasshopper
1

Hi there,

Apologies if the solution for this topic has already been explored, but I have not found anything that has helped me so far.

The meshes that I join together do not appear as ‘Invalid Meshes’ but when I bake them and check them in Rhino they keep coming up as ‘Bad Meshes’.

I don’t have a particularly good understanding of how meshes really work, but they keep showing up as bad mashes no matter what I try. Can someone please explain to me whats going on here?

Thanks in advanced,

Nick

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251001_Bad_Mesh.gh (14.4 KB)

2

After downloading your example wanted to install 3-4 plugins. Can you provide a simpler version NO plugins used?

3

Hi Eef, thanks for reaching out.
Here is a version of the script without any plugins. It still yields the same problem after baking the meshes. The Repair Mesh command reports that they are ‘bad’ meshes

251002_Bad_Mesh_NO_Plugins.gh (11.4 KB)

4

Try this solution.

251001_Bad_Mesh a.gh (28.1 KB)

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5

Hi Leo, this is a great idea, however I want to be able to break them apart down the line. So i do lose information doing this. It’s why I haven’t been welding the meshes together.
The method youve shown also encounters an discrepancy around certain corners.

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6

251001_Bad_Mesh b.gh (24.6 KB)

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7

Thanks Leo, while this does work, I do want to understand why my original method keeps producing ‘bad’ meshes. It keeps telling me that the mesh has overlapping faces. Perhaps this means that my input curves don’t meet edge to edge as cleanly as they should, although that’s something I’m not sure how to test. As far as I can tell they look perfectly flush.

8

One reason this fails is because some of your adjacent input curves don’t share all corners.

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The selected curve on the left has no vertex on the T-junction towards the right side. This leads to a non-manifold situation.

You’ll have to split the curves or add control points.

One of the next problems is that offset eliminates these extra vertices which aren’t corners. You can use the offset loose component instead.

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I chose to loft the individual line segments.

The meshes are joined and vertices are aligned. You see how many vertices are aligned…

The result is thickened so we could see non manifold edges if there were any but there are non.

The result looks correct in Rhino and no anomalies are shown running the check command.

251002_Bad_Mesh_weaverbird.gh (18.7 KB)

Weaverbird is used for the thickening of the mesh but it’s not essential.

9

Beautiful stuff, thank you so much! Also nice to hear for you, Martin :slight_smile:
I’ve never used/understood what Shift Paths does, but it seems to do the same thing as Trim Tree here. Is there a difference?

10

I don’t think there is a difference in most situations.

11

Maybe this plugin could help.

Clipper2GH | Food4Rhino

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