The new build that fixes this is in alpha and should be released soon.

Are you using the Mac build? Regrettably we have not gotten the new subtraction library working on Mac so it does not work as robustly as the PC. If you have access to a PC you can try to do it there. It might not work though. Subtracting two meshes is an incredibly difficult problem and sometime it just doesn't work right.

We have tracked it down and fixed it in development and will make new builds soon.

This problem (as far as I know) only happens in a design tab when there is no printer open. You can work around it by creating and opening a printer. You do not need to connect to it. Please let me know if you are seeing it under other conditions.

Sorry about that.

You need to have a printer setup for this to work. We have filed a bug for this issue and will make sure that you can export from a design tab without setting up a printer.

If all you want to do is export STLs it does not matter what printer you setup.

Thank you.

Have you checked the Baud Rate? It may need to connect at 115200 but the default is 250000.

That is the first place I would look.

If that doesn't work you should check and see if you can connect with just a terminal program.

MatterControl, like most everything in the real world, fall under many licenses. The code in GitHub is under the license it states (typically BSD). Some of the plugins are copy write MatterHackers. The name 'MatterControl' is a TradMark of MatterHackers. Basically, depending on what you want to do, it can be complicated.

If you want to get the source and build it or contribute a fix, or you want to build a new feature that you run your self, absolutely. If you want to distribute a new piece of software and call it MatterControl, that is not a permission in the license.

The simple answer is, you can probably do whatever it is you want within the license as is. The goal is MatterControl is open source software and the complexity is only in the places where there are other considerations, like marketing or user security.

I can describe it more from a use perspective. I have had PLA parts in my car on a hot summer day and they warped. I have had a PETG phone holder in my car (that slides into the CD slot) for the last 2 years and it has never had any warping or softening problems.

Very hot internal car temp:

PLA: BAD
PET: GOOD

You probably need to download and install the Visual Studio Redistributable from Microsoft. This is installed on most computers but it is possible yours does not have it.

You can find it here.

I also recorded a gif of how it should work. If this is what you are doing, but not getting the results you expect, it is probably that you need to install the redistributable from Microsoft.

Thanks for letting us know what fixed it. I will make sure we address that right away.

You should find both the hotend and the bed controls both at the top right of the main display and within the controls tab.
Here is a gif I made that should be the same as what you are seeing on your screen.