Offset curves to masters

sorry if my question looks stupid because I just started using glyphs,
I’m trying to make a monoline font, and i wonder if its possible to use “offset curve” filter as a master to automatically generate different weights of the font?

Not quite sure what you mean with ‘filter as master’, but I am pretty sure you will find the answer in the Monoline tutorial:

oh, i just figured out how instances work, i didn’t know when you export the font every instance will be a separate font. thank you
but is there a way to visually see the offset filter for different instances? when i enable “show preview offset” it only shows a default thickness. what im trying to do is using offset filter for different weights, and i need to see the weights to space and kern the font. thats why i mentioned “masters”

Your master is just your monoline. You can see instances below in the Preview area.

It shows the last values used in Filter > Offset Curve.

preview area is blank! doesn’t show anything for me

do you mean preview area of “font info > instances” window?

No in the main window. If you click on the Eye symbol in the bottom left in an Edit tab.

this preview is empty for me! does not show anything!

You need to pick the instance you want to preview from the little pop up menu.

after several tries I could finally figure out how to enable preview!
but for some reason its showing the preview upside-down! any idea?

See the blue “F” on the bottom, left of the slider: that means you activated the Flip mode. Click it again and your text should be the right way up!