The rendering pipeline remains the same as the sequential algorithm, with polygon calculations (transformation, clipping, hidden surface removal) and pixel calculations (rasterization).
Both types of calculation are completely independent, so can trivially parallelize over polygons or pixels. However there are the usual problems of load balance and communication overhead that need to be overcome to get good performance, which is particularly crucial for real-time animation.
One advantage in doing animations is that successive frames are very similar. This allows dynamic load balancing, since the computational load for current frame can be used to load balance the next frame.