Why cant I booleanUnion this?

You see the curves where its build from.
I lofted the colours together to get the closed 2 breps. For the middle piece i just EdgeSrf.
Why is this not BooleanUnionable?

NotAbleToBooleanUnion.3dm (271.7 KB)

Hi Jordy

If you explode the small connecting part, there’s a very skinny surface right at the bottom seam. I’m guessing that’s causing the trouble. Also the one side is not quite intersecting. I fixed it manually, deleting the skinny surface and trimming the sides by hand - then joining the whole thing with no problems.

HTH, Jakob

NotAbleToBooleanUnion_fixed.zip (101.3 KB)

Oke I got rid of the small part.
How did you do the second?

AndNow.3dm (306.3 KB)

This is how far I got.

BU will generally not work with non-planar coincident surfaces. I’d just go at it at the surface level- ExtractSrf and delete the sides of the small piece, then use the edges of the small piece to trim the face of the larger one and then Join.

AndNow_PG.3dm (436.8 KB)


Oke I do what you tell me.
Extract the 2 circle surfaces. Explode the small one. Delete sides of small one. Use Edges to trim Circle. Then join all up. Result is an open PolySrf

ResultOpenPolySrf.3dm (325.0 KB)

You have two naked edges.

Extract the surfaces and delete them.

Select the object and use _DupBorder

Use PlanarSrf on the resulting closed curves to recreate the two surfaces that you deleted at the start. Select it all and join and you have a valid closed Polysurface.

Oke thats weird that that works but oke :stuck_out_tongue: The trimmed srf is created by the other crv that I now use to create a planar srf.


Hi @jordy1989

I did almost what @sochin did: extract and delete the small end-faces and then used cap to replace them.

Cheers, Jakob

@Normand yep cap straight after deleting the faces would have been quicker :slight_smile:

Nice. Edited in my grasshopper document and its working great :slight_smile:

I can adjust:

  • Rotation left and right sepperate
  • Sizes
  • thickness
  • distance between
  • width

Could use the Clusters well here because most of the things are used 2 to 3 times :smiley: