GH Preview display scrambled on Mac

I have an annoying issue with corrupt display of a Preview in the perspective view. See two attached files (Bad and Good).

Just moving the cursor a little in the Rhino perspective window switches between the two display outputs.

I have a mid-2011 MacBook Air. I see this condition (so far) only with this particular GH routine that generates a propeller, so I suspect it has something to do with how I construct the geometry and maybe how the display parameters are set up. Not sure where to look next.

Sorry for the delayed reply. Can you post the Grasshopper definition here so we can attempt to reproduce this issue on our machines?

Attached is a version that causes the “problem”. This remains very much a work in progress, so since my 1st post, I have developed a more recent version that does not seem to scramble the display as badly as before, but not sure why.

One thought I have that might be worth exploring some… can the model tolerance have any effect with this? Each blade is a loft of some section curves. Mostly because I have not figured out a good way to define the blade tips at the micro level, I have just been putting section curves at the tip, but making them small. The section curves at the very tip of the blade sometimes are very small (something I need to check into). I have not been checking how small the tip curves get, but if their size is on the order of the tolerances of the model, I can guess that some problems might occur. (89.0 KB)

Thank you for the definition. After quite a few attempts, I’m not able to reproduce this on my machine…it looks very good to me:

Can you please provide some additional information? Please navigate to Rhinoceros > About Rhinoceros > More info… > Copy to clipboard and paste the content back into a reply here. I suspect this is an Intel GPU that is problematic.

Hi Dan,
I just now saw the request for more info below the image. Here is the info you asked for. Hopefully, I will get a new Mac laptop in the near future, and the problem will go away.

Software information

Software versions
Rhinoceros version: 5.4.2 (5E411)
Rhinoceros path: /Applications/
IronPython version: not installed
Language: en-US (MacOS default)
macOS version: Version 10.13.6 (Build 17G65)


Third party kernel extensions
com.rim.driver.BlackBerryUSBDriverInt (0.0.68) 5794FFBC-214B-B40A-95A5-07DA0A6402B6
org.virtualbox.kext.VBoxDrv (5.2.10) B172CB4D-2DAC-34A3-B1ED-8927A492021C
org.virtualbox.kext.VBoxUSB (5.2.10) 18BFD538-2E5A-328C-B8BF-DF95DFDDFC6F
org.virtualbox.kext.VBoxNetFlt (5.2.10) 97411DA8-28E3-3954-85D4-10B616336375
org.virtualbox.kext.VBoxNetAdp (5.2.10) 4A140B73-8C07-3948-8928-D8700E8C7F8B
com.avast.FileShield (4.0.0) 3CFF7D43-06E2-34A2-94F8-316DAB3215BC
com.avast.PacketForwarder (2.1) ED7157CF-9D07-3FAB-9B10-36302914C357

Hardware information

Computer hardware
Hardware model: MacBookAir4,2
Processor: Intel Core i7-2677M CPU @ 1.80GHz
Memory: 4 GB
Architecture: Intel 64 bit

Video hardware
Graphics: Intel HD Graphics 3000 384 MB
Memory: 384 MB
Screen size: 1440 x 900
Displays: Color LCD (128dpi 1x)

USB devices
Apple Inc.: Apple Internal Keyboard / Trackpad
Apple Inc.: Bluetooth USB Host Controller
Apple: Internal Memory Card Reader

Bluetooth devices

OpenGL information

OpenGL software
OpenGL version: 2.1 INTEL-10.4.14
Render version: 2.1
Shading language: 1.20
Maximum texture size: 8192 x 8192
Z-buffer depth: 24 bits
Maximum viewport size: 8192 x 8192

Implementation settings
Use texture compression: No

Appearance settings
Antialiasing: 2x
Mip map filtering: None
Anisotropic filtering: None