Trimming several surfaces with several contours - error?

Done a video showing my pipeline workflow so you can better understand my point and uploaded it as usual for YouTube and only people with the link can see it (video not listed on YT)


Also uploaded 2 Rhino 7 files (input.3dm and output.3dm so you can replicate my intentions and test for yourself

INPUT.3dm (1.0 MB)
OUTPUT.3dm (2.6 MB)

My Rhino version:

Is There A Reason For Trimming Several Surfaces With Several Contours Acting Different If You Have 1…2…3…Or 4 Contours???.. I Mean…
A Small Number Of Contours Give A Different Result When You Neeeeed
To Do Fast Modelling And Select All The Contours?
We Can’t Go Fast… Why?

Let’s See…
Let’s Make A Copy Of Objects So We Can Reproduce Second Time…

Curves Were Projected On The Surfaces… Tolerance 0.01
Low Number Of Contours…
Trims Well And Faster Calculation… (Faster Of Course!!!)
Works As Expected… But!!!

A Few More Number Of Contours…
We Get All Trimmed Surfaces With A Lot Of Errors…
Pay Attention Please That I Have Extendcuttinglines=No And
Apparentintersections=No!!! (So… It Must Do Well And Simple)

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Hello - if you call trim on a pile of surfaces with a pile of curves, each curve will try to trim the targets - they may be pulled or projected onto the target surfaces. In addition, your surfaces do not meet up very cleanly, meaning the curves do not meet end to end which is messier still.
I would clean the surfaces so that they can be joined, Join them, then split with a clean set of curves.

For example - this surface is trimmed ‘wrong’ by these two curves:

because the far curve is projected perpendicular to its plane:

That is just how Trim works - if you ask for a lot of trimming objects, they are all considered when you click on a target.

The contours in this file do not meet because the surfaces do not meet cleanly.


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