Polygons POLY_F3/F4 FT3/FT4 G3/G4 GT3/GT4

[Pepe31]

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)

[djmips]

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