How do I solve the open brep issue in Grasshopper?

Hi everyone,
I am a beginner in GH. I was trying to import a closed mesh and calculate the geometry of the mesh. I am trying to create a sketch loft and calculate the volume of the mesh model which created from the sketch loft. However, an error existed which stated that the curve generate from the loft is not closed or the volume cannot be computed from an open brep. Here is the gh. mesh (30.2 KB)
Also, the imported mesh model file. convex hull.obj (10.7 KB)

You need to join the contour curves before the loft as some of them will be in pieces:

It’s a pretty messy loft doing it the way you’re doing it, but anyway this is the result.

Thank you for solving the curve issue!! However, when I try to import another closed mesh, another problem appears when the loft is created an error exists and stated “volume cannot be computed for an open brep”. Is that means the loft become a open mesh? How can I solve the problem?

Here is the mesh.RS_1_3_SM.obj (3.5 KB)

Sometimes I found there is a capping issue too…

What’s the goal of all this?

A sketch or example image would be helpful

I want to calculate the geometry of the mesh model and compared the volume of the sketch loft created based on the mesh model. I cut the mesh with three planes:XZ, XY and YZ. I can adjust the cutting contour resolution of each plane.

I just imported your obj and it worked fine for me in all three directions. Check you have the straight loft in the loft options, that’s all I can suggest, sorry:

That’s the interesting part…when I set the resolution into 10, the error exists, but when I set 15, there is no error anymore…

Same topic:

Capping algorithm failed to return a result in cap holes - Grasshopper - McNeel Forum

that is another topic that I created…

With the same problem

If you look closely, the first curve made by the contour component is non-planar, which means the resulting brep will not cap (it needs planar curves). You’ll get a more reliable result by using a mesh-plane intersection when generating your curves, attached is an example.

mesh anlayze (edit).gh (12.7 KB)

Whichever way you do it, the resulting brep is a little bumpy, so you may wish to rebuild the curves and alter the seam position before lofting (I’m not going to do that though). Best of luck with it.


Please don’t post the same question again elsewhere, it will clog up the forum if everyone did that. I’m completely in agreement with Martin here, be grateful for the free help received and treat the forum with respect.
Thanks, John.

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Thank you so much for your response. I thought that is a different issue so I started another topic, sorry for the disturbance. I am a beginner in grasshopper, thank you all of you being a teacher for all the skills!