The optional size attribute defines a recommended size for visualization of an infinite drawable element such as plane, cylinder, axis, etc., or objects without explicit geometric parameters (e.g. coordinate system).
The optional transparency attribute defines the transparency property of a model entity.
Source
<xs:complexType name="CADCoordinateSystemType"><xs:annotation><xs:documentation>The CADCoordinateSystemType defines the Cartesian 3D coordinate system in the model space.</xs:documentation></xs:annotation><xs:complexContent><xs:extension base="DrawableBaseType"><xs:sequence><xs:element ref="CoordinateSystemCore"><xs:annotation><xs:documentation>The CoordinateSystemCore element defines the mathematical core of the coordinate system.</xs:documentation></xs:annotation></xs:element></xs:sequence></xs:extension></xs:complexContent></xs:complexType>