Grasshopper preview occasionally disappearing from Top viewport

I’m having an issue where the GH preview disappears from the Top viewport but is still visible and fully normal in the others.

If I restart Rhino the preview comes back and behaves normally, at least for a while. As you can see, this doesn’t need a large or complicated script to happen.

Because it’s an intermittent issue this is going to be a pain to nail down (is it cured or just hasn’t happened yet?), so before I start disabling all my plug-ins has anyone else seen and resolved this?

Running Rhino 7.19.22130.15001, 2022-05-10, but this happened in previous SRCs.


Is this happening with any type of curve or just character outlines?

Here’s another topic but in contrast to your problem the entire GH preview disappears:

There is a known bug where if Grasshopper generates any geometry far enough away from the origin, the Grasshopper preview display stops working.
Then Clicking 4View is enough to reset it though, so you don’t have to completely restart Rhino.

I can’t see anything in the definition in that screenshot that would be creating very distant geometry, so I’m not sure if it’s the same issue.
Can you post the file?

Hi Martin,

This can happen with any GH preview items, it isn’t specific to curves, whether derived from character outlines or not. It is always just the Top view preview that vanishes. It is always the entire preview, never a subset.

Thanks for your interest

Hi Daniel,

It is very unlikely that there is any distant geometry in the file, certainly not intentionally - although it has been pulled from a file that was pulled from a file that was… etc

Here are the files - they will almost certainly not display the errant behaviour on re-opening, of course.

GH Preview Not In Top.3dm (143.4 KB)
GH Preview Not In (15.3 KB)


Indeed, I can’t reproduce the issue. Any idea of a sequence steps that might cause it to happen?

One thing I did notice is that your curves are a tiny distance (1e-14) below the XY plane, not sure if that is relevant though.

I don’t have any sense of a series of steps or a particular action unfortunately. And I’m not observing the Rhino canvas continuously while I’m working in GH, so I may not be aware of the point where this happens.

The curve z-positioning is probably a rounding thing - the curves have been manipulated quite a lot by now.

If no-one else chips in with experience of this I’ll start removing plugins. Probably Bongo 3 first as it’s a beta and has its own previews.