I noticed that when I move an extruded face back to its original position, it will leave some weird faces that are rendered only from the back side. It’s also interesting that these faces take only half of the previous height of the extruded version.
I tested this with a factory reset Rhino 9 Beta that only has two imported custom display modes. Everything else is 100% stock. I have the latest Nvidia drivers, too.
Move the upper face down to trigger the bug.3dm (89.2 KB)
Not able to repeat in the latest. Please run SystemInfo in the Rhino command line and post the results.
Rhino 9 SR0 2026-6-30 (Rhino 9 BETA, 9.0.26181.12303, Git hash:master @ 63db21acdecff631b4b3c30057580aaff9bf8c35)
License type: Commercial, build 2026-06-30
License details: Cloud Zoo
Expires on: 2026-08-14
Windows 10 (10.0.19045 SR0.0) or greater (Physical RAM: 16GB)
.NET 10.0.2
Computer platform: DESKTOP
Standard graphics configuration using OpenGL
Primary display: NVIDIA GeForce GTX 1660 Ti (NVidia) Memory: 6GB, Driver date: 7-2-2026 (M-D-Y). OpenGL(4.6.0 NVIDIA 610.74)
> Accelerated graphics device with 4 adapter port(s)
- Windows Main Display attached to adapter port #0
OpenGL Settings
Safe mode: Off
Use accelerated hardware modes: On
GPU Tessellation is: On
Redraw scene when viewports are exposed: On
Graphics level being used: OpenGL 4.6 (primary GPU’s maximum)
Anti-alias mode: 4x
Mip Map Filtering: Linear
Anisotropic Filtering Mode: High
Vendor Name: NVIDIA Corporation
Render version: 4.6
Shading Language: 4.60 NVIDIA
Driver Date: 7-2-2026
Driver Version: 32.0.16.1074
Maximum Texture size: 32768 x 32768
Z-Buffer depth: 24 bits
Maximum Viewport size: 32768 x 32768
Total Video Memory: 6 GB
OpenBLAS: OpenBLAS 0.3.30 DYNAMIC_ARCH NO_AFFINITY Haswell MAX_THREADS=64.
Rhino plugins that do not ship with Rhino
Rhino plugins that ship with Rhino
C:\Program Files\Rhino 9 WIP\Plug-ins\Commands.rhp “Commands” 9.0.26181.12303
C:\Program Files\Rhino 9 WIP\Plug-ins\WebBrowser.rhp “WebBrowser”
C:\Program Files\Rhino 9 WIP\Plug-ins\rdk.rhp “Renderer Development Kit”
C:\Program Files\Rhino 9 WIP\Plug-ins\RhinoScript.rhp “RhinoScript”
C:\Program Files\Rhino 9 WIP\Plug-ins\3dxRhino.9.rhp “3DxRhino.9”
C:\Program Files\Rhino 9 WIP\Plug-ins\IdleProcessor.rhp “IdleProcessor”
C:\Program Files\Rhino 9 WIP\Plug-ins\UpdatesAndStatistics\UpdatesAndStatistics.rhp “UpdatesAndStatistics” 9.0.26181.12303
C:\Program Files\Rhino 9 WIP\Plug-ins\RhinoRenderCycles.rhp “Rhino Render” 9.0.26181.12303
C:\Program Files\Rhino 9 WIP\Plug-ins\rdk_etoui.rhp “RDK_EtoUI” 9.0.26181.12303
C:\Program Files\Rhino 9 WIP\Plug-ins\NamedSnapshots.rhp “Snapshots”
C:\Program Files\Rhino 9 WIP\Plug-ins\MeshCommands.rhp “MeshCommands” 9.0.26181.12303
C:\Program Files\Rhino 9 WIP\Plug-ins\Displacement.rhp “Displacement”
C:\Program Files\Rhino 9 WIP\Plug-ins\SectionTools.rhp “SectionTools”
lets get you on the latest.
After 58 minutes the latest Rhino 9 Beta was finally installed ((9.0.26188.13293, 2026-07-07)
Commercial). No idea why it took so long…
However, even though it’s 100% factory reset and with zero customization, I got the following bugs:
The 2nd bug is reported in another thread:
Rhino 9 SR0 2026-7-7 (Rhino 9 BETA, 9.0.26188.13293, Git hash:master @ ac87238b2f9b57fd23752c796764855762dd1390)
License type: Commercial, build 2026-07-07
License details: Cloud Zoo
Expires on: 2026-08-21
Windows 10 (10.0.19045 SR0.0) or greater (Physical RAM: 16GB)
.NET 10.0.2
Computer platform: DESKTOP
Standard graphics configuration using OpenGL
Primary display: NVIDIA GeForce GTX 1660 Ti (NVidia) Memory: 6GB, Driver date: 7-2-2026 (M-D-Y). OpenGL(4.6.0 NVIDIA 610.74)
> Accelerated graphics device with 4 adapter port(s)
- Windows Main Display attached to adapter port #0
OpenGL Settings
Safe mode: Off
Use accelerated hardware modes: On
GPU Tessellation is: On
Redraw scene when viewports are exposed: On
Graphics level being used: OpenGL 4.6 (primary GPU’s maximum)
Anti-alias mode: 4x
Mip Map Filtering: Linear
Anisotropic Filtering Mode: High
Vendor Name: NVIDIA Corporation
Render version: 4.6
Shading Language: 4.60 NVIDIA
Driver Date: 7-2-2026
Driver Version: 32.0.16.1074
Maximum Texture size: 32768 x 32768
Z-Buffer depth: 24 bits
Maximum Viewport size: 32768 x 32768
Total Video Memory: 6 GB
OpenBLAS: OpenBLAS 0.3.30 DYNAMIC_ARCH NO_AFFINITY Haswell MAX_THREADS=64.
Rhino plugins that do not ship with Rhino
Rhino plugins that ship with Rhino
C:\Program Files\Rhino 9 WIP\Plug-ins\Commands.rhp “Commands” 9.0.26188.13293
C:\Program Files\Rhino 9 WIP\Plug-ins\WebBrowser.rhp “WebBrowser”
C:\Program Files\Rhino 9 WIP\Plug-ins\rdk.rhp “Renderer Development Kit”
C:\Program Files\Rhino 9 WIP\Plug-ins\RhinoScript.rhp “RhinoScript”
C:\Program Files\Rhino 9 WIP\Plug-ins\3dxRhino.9.rhp “3DxRhino.9”
C:\Program Files\Rhino 9 WIP\Plug-ins\IdleProcessor.rhp “IdleProcessor”
C:\Program Files\Rhino 9 WIP\Plug-ins\UpdatesAndStatistics\UpdatesAndStatistics.rhp “UpdatesAndStatistics” 9.0.26188.13293
C:\Program Files\Rhino 9 WIP\Plug-ins\RhinoRenderCycles.rhp “Rhino Render” 9.0.26188.13293
C:\Program Files\Rhino 9 WIP\Plug-ins\rdk_etoui.rhp “RDK_EtoUI” 9.0.26188.13293
C:\Program Files\Rhino 9 WIP\Plug-ins\NamedSnapshots.rhp “Snapshots”
C:\Program Files\Rhino 9 WIP\Plug-ins\MeshCommands.rhp “MeshCommands” 9.0.26188.13293
C:\Program Files\Rhino 9 WIP\Plug-ins\Displacement.rhp “Displacement”
C:\Program Files\Rhino 9 WIP\Plug-ins\SectionTools.rhp “SectionTools”
Even when I reset the program multiple times in a row and use DirectX, the bug with this particular model persists. Here is a video of the whole process:
Thanks for checking. This does look like a video caching issue, so far it appears specific to windows 10 and your gpu (which is getting later in life)
Thanks for reporting RH-96824 Moving an extruded face back to its original position leaves stray back-facing display faces
It’s worth mentioning that when I scaled down the model at the 3:25 minute of the video, there was not any leftover geometry in place of the previously extruded upper face.
Likewise, when the model was much larger at the 3rd minute of the video, the leftover geometry was smaller compared to the initial state of the model.
P.S. As for my GPU (Nvidia GTX 1660 Ti), it’s still suitable even for medium to complex car projects. 
At this moment it’s not worth it to buy a new GPU and RAM with the recent crazy prices.
the life expectancy physically on a nvidia gpu is 5-8 yrs, technical life expectancy is about half that. I tell people if they buy a new nvidia it should be good to run the latest softwares for around 5. yrs. Your model was released in 2019, not ancient by any means but in its twilight yrs.
Well, I built my PC back in 2014 and it’s working great so far. The only issues I have is with random crashes while working with files above 2GB in size or with very dense scan data consisting more than 10-20 million polygons. For regular NURBS surfacing of car bodies it’s blazing fast with Rhino 7’s great optimization. In fact, a few years ago it ran Nvidia GTX 960 2GB and 8GB of RAM, and it was also very good for NURBS surfacing. Now the RAM is 4x4GB DDR3 and the GPU is Nvidia GTX 1660 Ti 6GB. Everything else is from 2014.
I have been working in a few companies in the recent years and I was not impressed by their modern workstations. The only real advantage was the ability to work with super complex scan data that my PC can’t handle. But their advantage is negligible when it comes to NURBS surfacing (just a faster framerate).
My laptop Acer Aspire A717-72G (see the link below) is equally good as my desktop PC, despite having only 8 GB or RAM and a mobile GPU (Nvidia GTX 1050 4GB).
https://ardes.bg/product/acer-aspire-7-a717-72g-52e1-nh-gxdex-016-111937
