Abstract An attribute control scheme for the visualization of shielding relations among 3D objects, not restricted to the inflexible primitive-wise binding and the simple minded hidden parts removal, is presented. It is an important factor in 3D graphics how to visualize shielding relations to help users understand 3D geometry of objects. In almost all graphics systems currently used, shielding relations can be represented only by the hidden line/surface indication of which behavior users cannot control except for the selection from few alternative modes; non-removing, removing, and indicating. Such a restricted treatment is obviously insufficient to generate a wide range of pictures for a variety of user demands. In the scheme proposed here the attributes of the subparts of primitives are determined depending on the shielding environment. The determination procedure is application-user programmable. An experimental system named GRIP which implements this scheme is presented. The integration of a hierarchical structuring into GRIP, which makes it possible to determine attributes depending on the multiple shielding environments, is also described.
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