Cycles makes an interesting image

Oh well, stupid me.
Isn’t it interesting how clear it is to the developer, but not the user?

I had to learn this too. I agree that the UI could do with some (a lot) attention.


FYI, I have found the problem causing the rendering artifacts. The fix should be available in the next public WIP.

Hi Jeff,

sorry, I didn’t have enough fantasy to see the cause.

Regarding RH-40810, I didn’t shoot myself.
It was a customer’s imported STP file.
Creator is Autodesk Inventor 2013.

Of course it is an option to change colors on the fly.
Other CAD do it at least with black or white, depending on the background.

Another solution is to have a gradient background by default in Rhino.
Then things like the above can’t happen.
The reason for non-visible objects is visible then.


Setting yellow as the object color is suicide.
But again, we often see imported files with yellow objects.


No worries… I realize that we could probably do something to make this type of problem more manageable. However, I see this kind of thing about once every 5 years. So either it’s not happening very often, or users are just changing the display color of objects when they run into it. Either way, it means this problem hasn’t become escalated enough to have anything done about it.

You can have several forms of backgrounds in Rhino, all coming from different places and different sources. So comparing against a background color could produce a false positive in the cases where a solid color is not being used, which means this really needs to be done at the pixel level…which itself would open a can of worms.

If time permits, I might dig into this more and see if a more generalized solution can be done in a relatively easy way.

Gradient backgrounds have existed in Rhino ever since I added them (about 18 years ago), and yet they still haven’t found their way into Rhino’s default display settings…That’s not a decision I can make, so we’ll have to keep waiting on that one.

You can set your object color to yellow if you’d like, but then I’d recommend setting your selection color to something other than yellow :slight_smile: That particular problem can manifest itself with the background as well. If you have a yellowish background, then chances are all of your objects are visible…but once you select one, it can blend into the background, thus making it invisible…same problem, but a different situation.

Anyways, thanks for the report…as I said, I’ll try to see if there’s more generalized solution that can be dropped in easily.



(6.0.17234.9201, 22.08.2017)

Sorry, the artifacts are still there…


Can you please attach the file that exhibits this problem?

Thank you.


Test.3dm (63.7 KB)

@nathanletwory Just curious: are all these issues related just to porting or does Blender show them too?

@Charles, thanks. I’ll have a look soon.

@AlW the original issue in this thread was due to a small change I made to a check value (changed to order of magnitude of an epsilon by one). The issue reported by @Charles looks like a z-fighting problem, most likely due to groundplane. I know more when I have looked into the matter.

edit: it turns out it is a z-fighting issue when a large model is on the groundplane (large coordinate-wise): RH-41019

edit2: and the fix is changing the nudge value. It should be in with the next public WIP.

RH-41019 should be fixed in the latest RhinoWIP. Please give it a try.

It’s not fixed:

(6.0.17241.13071, 29.08.2017)

Did you scale your object up?

No, not that I remember…
But anyway, let’s assume these are the objects that are needed.