How to create a shape/mask with a hole in it?

Question

In graphics illustration applications, it's common to support boolean operations on shapes and paths, like subtracting one object from another resulting in a compound path (like a group of sub-paths).  This provides the ability to create shapes with "holes" in them where background content can show through.  Is it possible to do this with two (or more) shapes (or masks) in Motion 5?  For example, if I draw a rectangle shape and a smaller circle shape inset within the rectangle, to have the circle as a "hole" in the rectangle so that as the rectangle passes in front of other objects they show through the hole?  If the answer is yes this can be done, can you please descibe how?  Thanks!

Answer 1

It's possible to create a lot of sophisticated masking effects in Motion and there are two different ways that can be used in combination or separately (depending on the type of object being masked -- some objects won't allow shape masks, but almost all objects allow Image Masks.)
To set up what's going on below: the bottom layer is a Clouds generator. On top of it is a Spirals generator.
The region in the center where the '8' figure is starts as a rectangle to which 4 circle shape masks are added. The Shape Mask tool is in the one to the right of the Text ( 'T' icon) tool in the toolbar at the bottom of the Motion window. When an "eligible" layer is selected in the Layers List its options will be selectable, otherwise it will stay dimmed.
The first two circle masks added to the Rectangle are arranged one above the other (visually) and their Mask Blend Mode is set to Intersect and the Invert Mask options are checked for both. Two more circle masks are drawn for the same rectangle shape and placed to form the "holes" for the figure 8. Their Mask Blend Modes are set for Add.
The region of the Spirals that form the outer border is another Rectangle Shape drawn to form the bounds. To that Rectangle I added an Image Mask (right click on the Layer and select Add Image Mask.) To the Image Mask sub-layer I dragged the original rectangle containing the 4 circle masks.
Finally to the Spirals generator layer I added an Image Mask and dragged the second rectangle on the that sublayer.
When objects are added to an Image Mask, Motion will automatically turn off those layers from being visible in the canvas.
When working with masks, especially several levels of masking, sometimes you have to think in opposites. For instance, originally, the inner rectangle is solid and the figure 8 is the cutout. When added to the second rectangle, the "state" is reversed. Where you see the spiral are the solid portions of the final composite mask. If you select the Invert Mask option of the Spirals Image Mask, the entire thing "flips" (and the spirals would replace the clouds and vice versa).
Shape Masks have four available Blend Modes (Add, Subract, Replace and Intersect). Shape Masks are "all or nothing" cutouts (with exception of feathering).
Image Masks use Alpha, Individual Color channels (R,G, or B) or Luma to determine transparency. Image Masks can also use bezier shapes as sources, making almost the same as Shape Masks in this respect, except that Fill Opacity can be used to vary opacity within masked areas.
HTH