What's the best way to cut out this surface from the other?

Rhino Rhino for Windows
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1

Hi there. As of recent I feel like I have been getting a grasp on Rhino and I feel like my design process has improved substantially. I have been able to diagnose problems with almost all issues except for the following.

Highlighted Cut Out
Highlighted Cut Out1389×774 195 KB

In the above image I am trying to use the highlighted surface to cut out a section from the circular surface below. However the problem is that I cannot get the highlighted surface no matter how I build it to cut the section out so that the points at the bottom of the cutout are sharp and meet precisely at the bottom of the circular surface (See following image).

Highlighted Apex
Highlighted Apex822×641 28.8 KB

The frustrating part is that I have done this exact cut before perfectly on another project with almost identical dimensions, I just don’t remember the exact process I used.

Let me know how I can achieve my desired result and what I am missing.

Here is the Rhino file:

Trim Help.3dm (971.1 KB)

Thanks in advance

2

Here is isn’t… :stuck_out_tongue_winking_eye:

Try uploading it again…

3

Whoops… fixed now. Thanks

4

Hi Neil - if I make a new small object - loft from the two arc curves you have in place trimming works.

image
image712×470 59.4 KB

-Pascal

5

Wow that was ridiculously simple… Thanks so much.

Would it possible for you to explain why sweep2,sweep1 or networksrf doesn’t work for this?

6

Hi Neil - Sweep2 should work - it does not, apparently because the result is degree 1 in the linear direction and the loft by default is degree 3 - if I make a ‘Straight sections’ style loft (= degree 1) then it also fails to get a complete intersection in exactly the same way.
i.e. this is a bug in the underlying surface-surface intersection routine…
RH-80954 SSX failure, works if moved

-Pascal

7

Ahh okay was wondering why it wasn’t working turns out its a bug. Thanks for the clarification.