Masked Moho object is a white square

[Jkoseattle]

I have imported a Moho object into my project, which consists of a switch group of images flickering back and forth in a cycle. Works great.

I then placed the flickering Moho object into a masking group so that is can appear to come out from behind a boulder. The masking seems to work fine, but while "behind" the boulder, the flickering Moho object (switch group) appears as a big white square instead of being completely invisible. What am I doing wrong?

The flickering switch group's masking settings are Add to Mask (though I also tried clear mask then add layer invisibly to it, same result), and the boulder is a vector layer with masking set to"Mask this layer"

I exported the animation and now what appears when "behind" the boulder is a white rendering of the flickering object (everything not transparent is white). It changes to its normal color when it is no longer covered by the boulder.

[synthsin75]

I'm having trouble understanding your description. A screenshot or two might help...or a file.

[Jkoseattle]

Oh never mind, I was yet again confused by the masking settings.

[synthsin75]

It sounded like you might have been adding the wrong layer to the mask, but I couldn't be sure. Glad you got it sorted.

[Jkoseattle]

I have never yet ceased to struggle with masking. The terms seem counterintuitive to me. For example “adding” to a mask sounds as if I am making the mask larger. If the “mask” is an area area which hides something, then logically, adding to that mask would imply increasing the area which does the hiding. But it is not that way. I am repeatedly confused by the reality that “adding” to a mask is actually taking away something from the mask.

It also confuses me that the object which is to be hidden by the mask needs to be above the object hiding it. Without masking, the correlation between placement in the layers palette and distance from the viewer is fairly straightforward. But once masking is introduced, an object which is further from the viewer in space may actually be higher up in the layers palette.

And don’t even try to get me to understand what “clearing the mask” then adding or subtracting something to it means....

[synthsin75]

I have never yet ceased to struggle with masking. The terms seem counterintuitive to me. For example “adding” to a mask sounds as if I am making the mask larger. If the “mask” is an area area which hides something, then logically, adding to that mask would imply increasing the area which does the hiding. But it is not that way. I am repeatedly confused by the reality that “adding” to a mask is actually taking away something from the mask.

It also confuses me that the object which is to be hidden by the mask needs to be above the object hiding it. Without masking, the correlation between placement in the layers palette and distance from the viewer is fairly straightforward. But once masking is introduced, an object which is further from the viewer in space may actually be higher up in the layers palette.

And don’t even try to get me to understand what “clearing the mask” then adding or subtracting something to it means....

"Add to mask" basically means to show this layer and have it ONLY show any that overlap above it. This is true whether the mask is "Show all" or Hide all". And "Add to mask invisibly" just means that layer isn't shown, but it still ONLY shows any that overlap above it.

In a "Hide all" mask, "Add to mask" does literally add to the mask. In a "Show all" mask, it constrains what is shown above it to the add mask.
Similarly, in a "Show all" mask, "Subtract from mask" literally removes from the mask, but in a "Hide all" mask, it constrains what is hidden above it to the subtraction mask.

The Show-Add and Hide-Subtract combos are mostly used where you either have a "Don't mask this layer" or a "Clear the mask" operation below it.

I don't know how useful it is, but I did a tutorial on masking ages ago. All the masking operations still work the same though: https://www.youtube.com/watch?v=n3bFbcSM9aE