If you find that you can’t see your mask, it might be because you’ve pressed the spacebar. The spacebar toggles the visible outline of your mask and any layers you have. So, if you want to hide or unhide your layers and masks, you can use the spacebar.
Why can't I see my Mask when I add it to the Simulation Window?
Describes the solution when you cant see your mask in Fire Studio 6 and 7.

Written by Rich Merritt
Updated over a month ago