Rhino6 surface display issue

hello everyone,

I encountered a wired issue as pictures show below:
The purple colour marks as back surface.

All these 3 boxes are extruded from Rhino6 command, and you can see when I zoom in, some of the boxes` surface got flipped. Any idea why?


Hi Lei - A few things: does this happen with any model or only specific ones? Since backfaces are not colored in the default display modes, please either attach your custom mode or describe the changes to one of the default modes. Finally, please run the Rhino SystemInfo command and post the result here.

Hi Wim,

the ONLY change in “shade” mode is shown below:
and here is the systemInfo.:

Rhino 6 SR13 2019-2-27 (Rhino 6, 6.13.19058.371, Git hash:master @ 17cd8b51accbe17dd04b48028f49d5e77a67f17b)
License type: Commercial, build 2019-02-27
License details: Stand-Alone

Windows 10.0 SR0.0 or greater (Physical RAM: 32Gb)
Machine name: DESKTOP

GeForce GTX 1050 Ti/PCIe/SSE2 (OpenGL ver:4.6.0 NVIDIA 417.22)

OpenGL Settings
Safe mode: Off
Use accelerated hardware modes: On
Redraw scene when viewports are exposed: On

Anti-alias mode: 8x
Mip Map Filtering: Linear
Anisotropic Filtering Mode: Height

Vendor Name: NVIDIA Corporation
Render version: 4.6
Shading Language: 4.60 NVIDIA
Driver Date: 11-29-2018
Driver Version:
Maximum Texture size: 32768 x 32768
Z-Buffer depth: 24 bits
Maximum Viewport size: 32768 x 32768
Total Video Memory: 4 GB

Rhino plugins
C:\Program Files\Rhino 6\Plug-ins\Commands.rhp “Commands” 6.13.19058.371
C:\Program Files\Rhino 6\Plug-ins\rdk.rhp “Renderer Development Kit”
C:\Program Files\Rhino 6\Plug-ins\RhinoRender.rhp “Rhino Render”
C:\Program Files\Rhino 6\Plug-ins\rdk_etoui.rhp “RDK_EtoUI” 6.13.19058.371
C:\Program Files\Rhino 6\Plug-ins\rdk_ui.rhp “Renderer Development Kit UI”
C:\Program Files\Rhino 6\Plug-ins\NamedSnapshots.rhp “Snapshots”
C:\Program Files\Rhino 6\Plug-ins\RhinoCycles.rhp “RhinoCycles” 6.13.19058.371
C:\Program Files\Rhino 6\Plug-ins\Toolbars\Toolbars.rhp “Toolbars” 6.13.19058.371
C:\Program Files\Rhino 6\Plug-ins\3dxrhino.rhp “3Dconnexion 3D Mouse”
C:\Program Files\Rhino 6\Plug-ins\Displacement.rhp “Displacement”

When I open a new file(no attchment nor copy-in), the extrusion is all fine. No back surfaces(as marked as purple colour). BUT, here is the file 191104_error file.3dm (909.9 KB) when I have these problems. Either you attach this file into a new file or create an extrusion geometry in this file, the problem occurs.


Hi Lei - I’m not having problems with the file that you posted with backfaces set to pink:

It looks like you are running a cracked version of Rhino and while that probably isn’t what is causing this, you might as well try with a legitimate copy.

You are running Rhino 6.13 - please update to the current 6.19. Also, your display drivers are getting somewhat old - Driver Date: 11-29-2018 - please try updating these as well.

Thanks Wim! I`ll try update to the new vision.