Section cut line offset error [arctic mode]

The section line within arctic mode after using clipping plane captured to file offsets from the cut object (please see white line in image attached).
*Tried to troubleshoot view settings for Arctic; nothing seems to fix the issue.


Sorry, I see your image, but I have no idea what is wrong with it.
Can you please post a simple file that shows the problem so an idiot like me understands it?
If I can understand and repeat the problem, I can get it on the defect list for fixing.


I think I can report the same edge offset phenomenon happening with “View Capture to File”. The dimension of the offset might be scale dependent and only seems to occur with the Artic display mode.

Attached is a comparison of Artic vs. Render png files from very simple clipped geometry. The clipping plane fill color for both is red, but zoom in to the edges to see the differences that are occuring.

I think the clipping plane position is correct but for some reason the geometry in Artic mode is not cut all the way back to the plane. This is for a perspective view.

Update to add: The lens length in the perspective view seems to be a factor in how much “extra” is shown - drastically different results from what is shown on screen.

Hello - if you have an example file that you can send us, that would be best- there is no good way to track this down otherwise.


This issue is still occurring in Rhino 7. I found this thread while searching for a solution, and in trying to fix it I think I have identified the cause. The issue seems to be related to the Ground plane settings (under Display mode options>Viewport settings). If Ground plane settings are set to custom and “On” is checked, any surfaces are clipped at a location closer to the camera than the plane, but if “On” is not checked, the surfaces are clipped at the correct location (which is in plane with the selected fill). It is important to also note that this is only in perspective projections. This doesn’t occur in parallel projections.

So, if ground plane shadows aren’t necessary this problem can be fixed by turning the settings off. It is late here so I will upload a sample file in the morning if Pascal or John are still interested in this?

I’ve had a bit more of a play around and the problem presents seemingly due the distance of objects in the scene from the clipping plane, and the severity of the issue is in proportion to object distance from the clipping plane. As per previous post this is only if ground plane settings are on, in perspective projections. This isn’t only in arctic mode, it will also affect Shaded (for example) if ground plane is turned on.

If all objects in the scene are close to the plane, the offset will only be perceptible at close range. When objects are distant from the plane the issue becomes readily apparent.
Luckily, if the scene is bound by another clipping plane, the problem reduces back to the extent of the model in the view but only if the objects are distinct from the object being clipped (I stretched the room to the distance I had copied other objects and bounding the clip made no difference).

This is the perspective shot. The model is a basic room 6x5m.

This is the perspective shot with groundplane on - difference is imperceptible at this scale.

This is a closeup of the cut model with the ground plane off (no offset). Clipping plane fill is by plane’s material, clipping edge is red to differentiate from fill

This is the closeup of the cut model with the ground plane on - clipping plane edge is visible in correct location but the model “leaks” forward of the clipping plane line ever so slightly

This is the cut model with a copy of the geometry copied 500 metres away in model (visible in the distance at middle right - although even a single curve being distant will have the same effect). You can see the leaking forward is quite pronounced here forward of the clipping line.

This is the bounded clipping scene. The leaking is reduced back to being imperceptible at this scale.

and this is the stretched model, with the ineffectual bounded clip - you can see the model leaking past both clipping lines.

I’ve attached the demo model for assistance in solving the issue. Hopefully this helps somebody!

clippingplane_demomodel.3dm (4.9 MB)