1. A multi-pass method of generating an image frame of a 3D scene, using a parallel graphics processing system having a plurality of graphics processing pipelines (GPPLs), including a primary GPPL, wherein each said GPPL includes a color frame buffer and Z depth buffer, and said GPPLs support an object-division based parallel graphics rendering process, wherein the 3D scene is decomposed into objects that are assigned to particular GPPLs for processing, said multi-pass method comprising: (a) during a first pass, providing a Global Data Map (GDM) to the Z depth buffer of each GPPL involving the transmission of graphics commands and data for all objects in the frame, to all said GPPLs to be rendered; (b) during subsequent passes, generating a complementary-type partial image within the color buffer of each GPPL using said GDM and a Z test filter supported by said Z depth buffer, and transmitting graphics commands and data of objects in the image frame, to only assigned GPPLs; and (c) after said subsequent passes, recompositing a complete color image within said primary GPPL, using the complementary-type partial images stored in the color buffers of said GPPLs, without comparing depth values in said Z depth buffers.