The fastest way to draw 3D objects with DirectDraw?

[Monstrum]

I've tried alot of methods using the BltLine function on a surface but can soeone tell me wich is the fastest way to do it.
Is it faster to draw the object on a small surface and then Blit it into the big backbuffer or should I just draw it directly on the backbuffer?
And also, should I use the buildt in BltLine or write one myself using SetPixel?