Your presentation has presenter notes but your MacBook has only one display?

Create a dummy display for the full-screen presentation, share that into the remote meeting/projector, and preserve the primary display for presenter notes, logtails, chat, etc.

Sounds like it'd be easier to just run your slideshow in a window and share that window. PowerPoint and Keynote can both do that.

Bonus to sharing only a window - you never accidentally show something you didn't want to, like that email or messages notification...

For those who don't know, in PowerPoint go to Setup Slide Show on the Slide Show tab and select "Browsed by an individual (window)" and then share that window. Great for Zoom et al.

I use OBS to handle the screen sharing because it is easily to misclick the wrong window that are not for public view. In OBS, it is binded to specific window titles and it is easily to edit out the black bar on the top of the PowerPoint that appeared in Zoom directly (without OBS). I have a few scenes set up this away and quicker to switch than doing it through Zoom itself.

This doesn't sound like the core use case though based on the README - it sounds like it's used for enabling HiDPI (aka not-blurry) scaling on less-than-4K monitors. So, using native resolution but not necessarily 1:1 DPI.

It is not just a monetary problem though. Sometimes you don’t have the required physical access or permissions to install additional hardware.

Hi, I tested the Screen Sharing scenario with BetterDummy running on an Intel headless Mac Mini 2018 running Big Sur. Works splendidly, all resolutions are available and resolution change works on-the fly through Screen Sharing!

Was looking for this exact thing a month ago [1]. Now, this.

I've given up the idea of connecting to mini over screensharing and connected a couple of displays to it, happily.

[1] - https://apple.stackexchange.com/q/428243/51800

Here is another reason this is useful:

If you connect a Mac (mini, MacBook pro, air) to an external monitor, AND this monitor is not recognized as "retina" (eg. Apple $4599 XDR) AND you are not running at the monitor's highest resolution, the screen will be blurry.

There are a lot of "ands" in the above sentence, but it's actually quite common situation. Retina monitors are expensive. For non-retina monitors, native highest resolution still renders objects too small for many people.

On MacBook Pro/Air the solution is to mirror the screens. The MacOS thinks that it renders to the retina screen and sends appropriate re-scaling to the external monitor. But mirroring has its problems. For example, expect ratio will be the same as MacBook's internal screen. This may result in black bars on the monitor, depending on its aspect ratio.

Also, in M1 MacBook Pro 2021, the aspect ratio is variable, due to the 72 pixels menu bar up top, going in and out. I am not sure what will happen when you mirror the screens there.

Hopefully the above software solves this problem.