PlayStation Development Network

Hello,

Can someone help me understand how the coordinates of the polygons POLY_F3/F4 FT3/FT4 G3/G4 GT3/GT4 etc. work? Because in the LibRef47.pdf documentation, the coordinates are in 2D because there is no Z component.
Are these coordinates in VRAM?
Are these exclusively 2D polygons?

Thank you for your answers.
(Google Translate)

This early GPU doesn't do transform and lighting, that's done on the CPU with the help of the GTE.