Outline
Add an outline on all objects of the layer having the effect. This won't work well if shown on top of the background color of the scene. Be sure to use an object acting as a background or a floor.

Parameters
- Thickness: how wide the outline is, in pixels.
- Color: the color of the outline.
Note
The outline is drawn inside the padding of the effect area. If a thick outline gets cut off at the edges of an object, increase the object's Padding so there is room for the outline to be drawn.
Reference
All effects are listed in the effects reference page.