Returns or sets the depth of the shape's extrusion. Can be a value from – 600 through 9600 (positive values produce an extrusion whose front face is the original shape; negative values produce an extrusion whose back face is the original shape). Read/write Single.
Example
This example adds an oval to myDocument, and then specifies that the oval be extruded to a depth of 50 points and that the extrusion be purple.
Set myDocument = ActivePresentation.Slides(1)
Set myShape = myDocument.Shapes _
.AddShape(msoShapeOval, 90, 90, 90, 40)
With myShape.ThreeD
.Visible = True
.Depth = 50
'RGB value for purple
.ExtrusionColor.RGB = RGB(255, 100, 255)
End With