# VASSAL Reference Manual Home > Module > Game Piece Palette > Game Piece > Area of Effect
## Area of Effect Trait
The 'Area of Effect' trait allows you to graphically highlight an area surrounding a game piece. The area is shaded with a specified color and transparency. Alternatively, you can point to a Map Shading component, contributing to the area that it draws. Use Map Shading: If selected, then the area of this trait will be added to the area drawn by the named Map Shading component (or subtracted from that area if it is of type Background). If not selected, then each piece with this trait will draw its own area, with overlapping areas shaded darker. Fill Color: The color of the area. Opacity: The opacity of the area. 100% is completely opaque. 0% is completely invisible. Radius: Distance, in local grid units, from the game piece that will be highlighted. If the piece is on a board with a Rectangular Grid or Hex Grid, this distance is in grid units and the shaded area will conform to the grid. Otherwise, it will be a circle with the given radius in pixels. Always Visible:If selected, the area is always highlighted when the piece is drawn on a Map. Toggle Visible Command:If not always visible, this is the right-click menu command to show/hide the highlighted area. Toggle Visible keyboard shortcut:If not always visible, the keyboard shortcut to show/hide the highlighted area.. Area of Effect applied to a Flat Top cloud counter. (Gray, 20%, 2) | Area of Effect property window. Area of Effect applied to a VASL FFE counter. (Purple, 40%, 1)