Options for exporting masters and instances from multiple master files in Glyphs are limiting and seem arbitrary. I can export instances, but I have to export all of them at once, and only to an OpenType font. I can export masters, but only as UFO files, but I get to choose which masters are exported. If I want to just export one master to a new Glyphs file, I either have to either import it from a UFO or copy the file and delete other masters and instances. If I want to export just one instance to a new Glyphs file, I have to export every instance and then save the one I want as a Glyphs file. If I only have one master I can export to OTF. But in a multiple master font I must create and configure an instance for each master to export them to OpenType fonts. Custom parameters that should be the same for every master and instance must be configured for each master and instance rather than just once for the entire font. There is nothing user friendly about this interface.
I propose that export menu allow users to choose between Glyphs, UFO, and OTF formats for masters and instances. Users should also be able to select which masters and instances to export rather than exporting all instances every time. Each custom parameters in a master should have a check box to apply it to all masters and instances so that things like vendor codes and vertical metrics can just be set once.
A better way to do this is:
In Font Info > Instances, select all instances and click off the "is active" checkbox. Then select the one(s) you want to export and click it/them back to active. Then go to the Font menu (not File) and choose Generate Instances.
That’s easier than what you were doing, but you’re right that some of this stuff could be streamlined in terms of interface.
What do you want to do with the master that you have to take it out of the Glyphs file? Perhaps there's an easier way to do what you intend.
You can edit multiple masters/instances at once, like eliason described for the Is Active checkbox. This applies to all the settings.
You already can put family-wide parameters into the family-wide cutom parameters, in the first tab of the Font Info. This screenshot, ironically, contains a vendor code and vertical metrics for the whole family.
I admit that some of this could be better documented. Rest assured, there’s something in the works.
What do you want to do with the master that you have to take it out of the Glyphs file? Perhaps there’s an easier way to do what you intend.
Export a work in progress to an OTF without creating an instance. Or maybe I want to start using the master as the basis for a new design (inline, condensed, etc.). I’m not saying this stuff will occur every day, but it does happen, and it might as well be simple. It seems like the Glyphs interface for exporting is an attempt to simplify something that was not complicated to begin with.
Rest assured, there’s something in the works.
I always assume the Glyphs team is working on something better. That’s why I provide feedback.