don't know who designed the 3D hardware in the DS.
keep in mind, that DS can only handle 120,000 textured, z-buffered, gouraud shaded, lit polygons per second. this is less than Nintendo64, the Sega Model2 board,
the Namco System22 board, the Sony Playstation, the Sony/Namco System11 board,
Videologic's PowerVR PCX1, and the 3Dfx Voodoo1.
DS' 3D graphics capabilities are.... well, we are talking about 3D roughly on par with a Rendition Verite V1000, one of the the earliest good 3D chips for PCs, which came out before 3Dfx Voodoo.
DS's 3D capabilities are extremely minimal, so don't let the 4 million vertices per second calculation speed fool you. that's like PS2's 66M or PSP's 33M or Xbox's 116M