It's still there in AC10, you just need to change the 3D Engine from OpenGL to the Internal Engine whilst in the 3D window. One way to change this is to open the 3D Window and with nothing selected, right click on a blank area, then choose 3D Window Settings... The following dialog is where you can change the 3D Engine.
Not sure I understand your question but here goes...
To save a 3D Perspective or axon to a line drawing you need to switch 3D Window to internal engine as Link suggested. Whether you use Hidden Line or Wireframe is irrelevant. Next, save as a 2d line drawing (.2dl) then open that .2dl in ArchiCAD and save out as .dwg.