In the upper left corner of the Motion desktop, there should be a little screen in which you can preview filters, behaviors and other things. Now the "gloom" filter won't play in the preview. Same with "glow". I used the effect once without any trouble. I could give an object a golden shine in no time. Now when applying gloom to an object, the object becomes black and I only have to items of the gloom filters which I can change in the Inspector: Radius & Amount. But no matter what I do, the object remains black.