360° Area Shape 4D is in the Highlight category of Alex4D 360° Effects:
Here is what the Final Cut Pro 360° viewer and the viewer look like when the 360° Area Shape 4D effect is applied:
The first parameter sets whether the shape is overlaid on the clip or drawn behind the clip (so the shape is visible in the transparent parts of the clip).
The next set of parameters control the fill, frame and shadow of the shape added.
Fill Colour and Fill Opacity control the way background looks. Uncheck Fill to turn it off.
Border Opacity, Border Colour and Border Thickness control the way the background frame looks. Uncheck Border to 0% to turn it off.
Front Blend Mode controls how the shape is drawn over the clip (or how the clip is drawn over the shape if the first parameter Shape is set to Behind Source).
Shadow Opacity, Shadow Colour, Shadow X offset, Shadow Y offset and Shadow Blur control the way the background shadow looks. Set Shadow Opacity to 0% to turn it off.
The next set of parameters define the area:
Area Centre, Area Size and Area Angle can also be set using the on-screen control.
Area Centre Limit stops the centre control from moving off the edge of the clip. Disable this if you want to keyframe this value so that the area can move off the edges of the clip.
Area Roundness controls the corners of the area. If Area Aspect Ratio is 1.0, a value of Area Roundness of 100 makes the area circular. A value of 0 makes the area sqaure.
Area Aspect Ratio defines the proportion of the width of the area to its height. 1 makes them equal. A value greater than 1 makes the area wider than it is tall. For example 2 makes the width twice the size of the height.