Rhino 8: Trouble with Clipping Plane in 'Pen' Mode with Shadows On

I know that’s a bit specific of a scenario (in “Pen” mode, with shadows “On”) but that’s my preferred display style for output, so hopefully there is a fix for this?

I get some really weird visual effects when in this mode. See below for example:

I’m not sure how to describe what its doing… but it doesn’t seem right.

all the best,


  • Macbook 2021, Apple M1 Max
  • OS 12.5.1 (Monterey)
  • Rhino Version 8 (8.1.23325.13002, 2023-11-21)

Hi Ed-

Thanks for the video clip. I’m attempting to reproduce this here and having some trouble. (It also might help if you shared a file.) In lieu of a file, I tested with this one…

  1. I opened PenShadowsTest.3dm (3.4 MB) in Rhino 8 (8.1)
  2. I enabled the gumball.
  3. I switched the Perspective viewport to Pen.
  4. In the viewport properties menu, I checked the Shadows box.
  5. With the gumball, I moved the clipping plane up and down in the Z axis.

I was unable to reproduce the weird flickering you are seeing.

I notice you are on macOS Monterey 12.5.1. I also tested this on macOS Monterey 12.6.8 and didn’t have any luck.

Sometimes Apple fixes driver bugs in this minor updates and I’m hoping that’s what’s happening here. I’d suggest you start by updating macOS Monterey to the latest today (12.7.1) and see if the issue persists.

Hi @dan

Thanks for the suggestions.

I updated to macOS Monterey 12.7.1 as you suggested (I didn’t realize I was that far behind…) and that does help a lot. There is still some weirdness with the lines (it seems like maybe the ‘shadow’ version of the surface is rendering on top of the lines somehow, which makes them look weird? Esp. in the back?) but it is better than the previous version with Monterey 12.5.1


I will update again to macOS v13.6.1 (Ventura) and see if that helps.


  • Macbook 2021, Apple M1 Max
  • OS 12.7.1 (Monterey)
  • Rhino Version 8 (8.1.23325.13002, 2023-11-21)

Any reason not to go to Ventura?

Hi @Japhy : No, nothing particular (except a general aversion to ever updating anything unless I absolutely have to :wink: )

But, updating to macOS Ventura 13.6.1 does not seem to have changed anything for me. See below:


  • Macbook 2021, Apple M1 Max
  • macOS 13.6.1 (Ventura)
  • Rhino Version 8 (8.1.23325.13002, 2023-11-21)


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Thanks for the giving it a go and the additional info.

I haven’t upgraded to Sonoma myself for that same reason. I’m happy with Ventura so far ( running it for a few months now)

Thanks for being willing to update even a little incrementally! (I know sometimes it really feels risky.)
Glad it helped!

Your videos help. I’m still concerned that we can’t seem to reproduce this issue on our end. I’ll try again with macOS Ventura 13.6.1.

It looks ok to me on macOS Ventura 13.6.1.

This is on a MacMini M2 Pro.

Hi @dan

I’d say that actually we are getting the same effect, don’t you think?

from your video, as you scroll down, it appears to ‘render’ (right word?) something on top of the rear cube which affects the lines there:

which is the same as what I’m seeing now that I’ve updated to Ventura. The effect is less ‘extreme’ than before with Monterey, but it’s the same peculiar effect I think?

You can also see a weird thing happening here, no?:

Its like the ‘upper’ (clipped) part of the big cube is still being shown, just in a transparent way that then affects the other items behind it?

my example file attached, along with my Pen.ini file, if that is helpful at all?

example.3dm (2.6 MB)
Pen.ini (7.7 KB)

I’m trying to see it in my video and I think I see something very momentary with the silhouette here…


@jeff could I please take a look at this? I’m sure I could log something here, but I think you might be able to give a clue as to why this is happening.

I’ll take a look at this later today… It looks and sounds similar to an item that’s already on my list.


Thanks! This one looks potentially related as well:

Hi again @ed.p.may

Is this more about what happens when dragging the clipping plane, or does it have to do with the final resulting frame?

Dragging the clipping plane undergoes all kinds of “make things as fast as possible” adjustments … So if the view doesn’t look 100% during the drag operation, then we’re not as concerned…but if things look bad or wrong once the dragging stops, then something(s) is busted…

What do you think?

Hi @Dan,

I think with the new 8.3 update (8.3.23346.14002, 2023-12-12) most of the issues seem to be resolved? Previously, the ‘cut’ object was always present and somehow ‘ghosted’ in a way that interfered with any edge geometry behind it, but now it seems to show pretty well by my test:

The geometry still ‘pops’ in/out of view when you move things around, but as you say: that’s not a huge issue, just a minor annoyance. The ‘still’ view now looks pretty good to me though I’d say!


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Great to hear!