Flickering external display

I have a strange issue using Rhino with an external display connected to my Macbook pro.

Under certain circumstances when moving the mouse around, the external display will turn off and on again. A sure fire way to trigger this is to start drawing a curve with Polyline or InterpCrv, place a few points and whilst still drawing the curve, mouse over some of those points. The display will then turn off momentarily (about 1-2 seconds) and come back on. This only seems to happen when hovering over points with object snaps enabled. With object snaps disabled the problem doesn’t happen.

This only affects Rhino and started maybe a couple of months ago. Has anyone else experienced this? Google hasn’t been any help.

Try HDMI or DVI-D cable or check PSU.

Finally had a chance to replace the display port cable and the problem persists. I can’t easily replace the PSU for the monitor, but I’m not sure why this would be the cause. I don’t see this issue anywhere else, just in Rhino

I’ve attached a short clip to show what’s happening:

Most Macbook Pros have two GPUs, the integrated Intel GPU that is part of the CPU chip and a second discrete GPU. Most of the time the integrated Intel GPU is sufficient to run macOS. Rhino, because of its graphics requirements, switches the computer to use the discrete GPU. The flickering could be due to a problem in the discrete GPU, which is required when running Rhino.

Please post your Rhino information (Rhinoceros > About Rhinoceros > More info > Copy to clipboard).

gfxCardStatus, small menu bar app (https://gfx.io), lets you see when your computer switches between integrated and discrete GPUs. More importantly, you can use it to set your computer to always use the discrete GPU. Do this, and see if you have display problems with other applications.

[quote=“honkytonk, post:1, topic:60262”]
the external display will turn off and on again.
[/the quote]

I’ve encountered same for years with a Mac Pro and external display. Happens infrequently. Cycling the power on the display usually makes it stop. While infrequent, it is rather disruptive when the affliction kicks-in.

I know it happens when using Rhino, because I’m in Rhino a lot, but I can’t recall if it happens in other apps, or when Rhino isn’t running in the background. Read - is Rhino seemingly related or unrelated, or simply a persistant external display bug? Until your report, I wondered whether it was my display or cables. Did the cable swapping long ago, to no effect.

I’ll try and remember to pay better attention and report back. Will experiment with your reported trigger too when I get a chance.

@honkytonk what display do you have?

I also have the same problem, and have done for some time across two different Macbooks and the same external display (Dell 4k connected via mini displayport). It usually happens whilst drawing/moving curves too. Appreciate any suggestions!

Apparently gfxCardStatus not supported on my Macbook due to not having dual GPUs, yet I have the issue. My graphic specs:

Intel Iris Graphics 6100:

Chipset Model: Intel Iris Graphics 6100
Type: GPU
Bus: Built-In
VRAM (Dynamic, Max): 1536 MB
Vendor: Intel
Device ID: 0x162b
Revision ID: 0x0009
Metal: Supported, feature set macOS GPUFamily1 v4
Color LCD:
Display Type: Built-In Retina LCD
Resolution: 2560 x 1600 Retina
Framebuffer Depth: 24-Bit Color (ARGB8888)
Main Display: Yes
Mirror: Off
Online: Yes
Rotation: Supported
Automatically Adjust Brightness: No
DELL P2715Q:
Resolution: 3840 x 2160 (2160p 4K UHD - Ultra High Definition)
UI Looks like: 1920 x 1080 @ 60 Hz
Framebuffer Depth: 24-Bit Color (ARGB8888)
Display Serial Number: 32R1F53P316L
Mirror: Off
Online: Yes
Rotation: Supported
Automatically Adjust Brightness: No
Connection Type: DisplayPort