Unable to Split Surface

Rhino
1

I can’t seem to figure out how to Split a surface.( split fails ).
In the image I want to split the red surface with the green surface.
Then use the resulting part of the red surface to ‘cap’ the green surface(after first trimming/removing the portion of the top part of the green down to the red surface)

Split_Surface
Split_Surface1551×1213 86.8 KB

Trim Surface with Surface.3dm (338.5 KB)

Edit:
This is the result I want which I got with patch. But I want the cap part to have the same surface bending as the red surface in the previous image.

Capped
Capped778×1066 131 KB

Edit:

I also tried doing an initial cap of the green with a patch and extruded the red - Then with both ‘air’ tight(no naked edges) - Tried doing a boolean difference. That failed too.

Boolean_Fail
Boolean_Fail954×1422 212 KB

Boolean Fail.3dm (414.7 KB)

2

The first problem is that there is a previously created intersection right at the exact points the new intersecting object is being created.

To fix it,

  1. Exploded the green object.
  2. Untrim the short tube so it is longer, fully intersection the red surface.
  3. Join the green surfaces together with the untrimmed surface.
  4. Use boolean Split command to split the green with the red.
  5. The result is two solid green objects. Capped properly.

image
image1024×1024 52.6 KB

1 Like
3

Thanks. I extended the tube so it would cross the red boundary to get a split.
Didn’t realize it already had a trim.

My other green posts had mirror positions so I was puzzled as to why a boolean split with resulting cap worked for those but not this one.

Going to have to get into the habit of remembering to check for untrimmed items in Rhino.

Thanks again.

4

The problem is a trimm exactly on the same intersection. Mostly this is a split, then rejoin.