Strange problem with Masks

I've got a still photo of an Italianate garden with a view through some pillars of an area beyond.

I'm trying to create three masks between the pillars so that I can place a cleaned-up Photoshop of the background, to be set back in 3D space to give a parallax effect.  A simple enough job for layers...

For the life of me, I can't get the three masks to work at the same time.

I can view through the centre cutout at the background, but if I activate the other masks, they appear to cancel each other out. The three are all on the same jpeg.

Any ideas anyone?


  • rgbii
    rgbii Website User Posts: 965 Just Starting Out

    Do you have the three masks set to Add with the invert on?

    If so, turn the invert off on all three and change them to Subtract, then add a mask that includes the entire frame and make sure it's the top mask.

    Not sure why, but this seems to be the only way I can get multiple subtract masks to work as I want.

  • Triem23
    Triem23 Moderator Moderator, Website User, Ambassador, Imerge Beta Tester, HitFilm Beta Tester Posts: 19,795 Ambassador

    You're cutting holes in the source image? 

    Try adding a new mask. Set it to ADD and make it cover the whole image. Move this mask to be top of the mask stack, then put in your three SUBTRACT masks. Hitfilm seems to want an ADD mask before you start punching holes--this same behavior had me confused two months ago. 

  • Robin
    Robin Website User Posts: 1,669 Enthusiast

    You can also set the topmost mask to Add and invert it, and all of the mask below that to subtract and not inverted. This will give you the same effect and spares you the additional mask, but is not as convenient if you ever want to switch around your mask order.

  • RobinDaviesRollinson
    RobinDaviesRollinson Website User Posts: 40

    Thanks guys, I'll try the extra mask. I did play around with the subtract/invert options to no avail...

  • RobinDaviesRollinson
    RobinDaviesRollinson Website User Posts: 40

    Just tried it - and it works!

    Thanks guys - you rock!!!