To change an object's color, use the TrueColor property provided for that object. You can assign colors to individual objects in a drawing. Each color is identified by an AcCmColor object. This object can hold an RGB value, an ACI number (an integer from 1 to 255), or a named color. Using an RGB value, you can choose from millions of colors.
Setting a color for the object overrides the color setting for the layer on which the object resides. If you want to retain an object on a specific layer but you don't want it to keep the color of that layer, you can change the object's color.
This example creates a circle and then colors the circle blue.
Dim color As AcadAcCmColor
Set color = _
Call color.SetRGB(80, 100, 244)
Dim circleObj As AcadCircle
Dim centerPoint(0 To 2) As Double
Dim radius As Double
centerPoint(0) = 0#: centerPoint(1) = 0#: centerPoint(2) = 0#
radius = 5#
Set circleObj = _
circleObj.TrueColor = color