Trim Bug in WIP

In Rhino 6 WIP I’ve noticed a weird issue when using the Trim command on multiple intersecting curves. To illustrate I made this quick example using the “Circle tangent to 3 curves” command:

Trim functions perfectly while in the Top View:

However the problem arises when using Trim in the Perspective view:

The curves do not split at the correct locations and clicking on those protruding tails just makes them split apart further into smaller segments.

That works fine here so there is something more file- or system-specific going on. Would you mind sharing a 3dm file?

Here’s my 3dm.Trim_Bug_01.3dm (53.2 KB)

I can reproduce this when I turn ApparentIntersections on.
I always keep mine at No, so this doesn’t bother me… :innocent:

This still happens to me even when turning off ApparentIntersections, which I’m glad to learn can be turned off by the way. :slight_smile:

Hi Derek, Wim - thanks for the report.


Hi Pascal,
I’m not sure if that means that you got it reproduced that it also does that with apparents turned OFF…

Hi Wim - here it is as you-all described - with ApparentIntersections=Yes the trimming is weird, with No, it’s OK.


Am I reading this wrong? :hear_no_evil:

ork. I see - well, here, with Apparent=No, the trims work as expected…

@Derek_Heming - can you verify that it does not work right for you is ApparentIntersections=No ?


Same here…

Sorry, I should have worded that more clearly. Yes this trim bug still happens for me in perspective whether ApparentIntersections=No or ApparentIntersections=Yes.

Hi Doug - ok, thanks, I’ve added a note to the YT item.


I looked at this bug and the problem I found required 3 things to make it happen

  1. The object picked to be trimmed was also chosen as a cutter.
  2. Apperent intersections set to true. In this case the the cutters are transformed to screen coordinates.
    without this option I believe the test that the cutter and the to_be_trimmed are the same object would make it so step 3 would not be used.
  3. The intersection of the 2d screen coordinate cutter and 2d to_be_trimmed curves was not a total overlap( i.e. from end to end) as it should have been.

RH-43352 is fixed in the latest WIP

Excellent news, thank you.