Select a face or plane in the graphics area that is parallel to the direction in which you want the surface to radiate for Radiate Direction Reference.
The arrow in the graphics area points normal to the selected reference, but the surface radiates parallel to the selected reference.
Select an edge or a set of contiguous edges in the graphics area for Edges To Radiate .
If necessary, click Flip Radiate Direction to radiate the surface in the opposite direction.
Select Propagate to tangent faces if the model has tangent faces and you want the radiated surface to continue along those faces.
Set Radiate Distance to determine the width of the radiated surface.