Type RealColor is a Real vector with 3 elements, {r, g, b}, and specifies the color of a shape. {r,g,b} are the "red", "green" and "blue" color parts. Note, r, g and b are given in the range 0 … 255.
type RealColor = Modelica.Icons.TypeReal[3](each min = 0, each max = 255);