i was writing about rendering wireframes in 3ds max quite a while ago and the solution offered by using a special mental ray shader works in maya, too; because maya now also has a built-in mental ray rendering system. there’s another way i recently discovered: use the maya vector renderer - but this one has a disadvantage, too: it renders surfaces with triangulated faces. so if you plan to keep the faces quadriliteral, use the hardware render buffer window:
choose window > rendering editors > hardware render buffer. in the window opened select render > attributes (the name of the tab should be defaultHardwareRenderGlobals). jump to the render modes section and change the draw style to wireframe. do a test render: if you’d like to change the default back- & foreground colors then choose another one through background color in the display options of the defaultHardwareRenderGlobals. the wire color can be changes through the color settings window (window > settings/ preferences > color settings).
to increase the overall quality of your wireframe render (please keep in mind the render is dependent on the graphics card installed), turn on multi pass rendering in the corresponding options and crank up the render passes. you also may try to render a larger image (resolution).
sounds too complicated? ok, let’s go for the third way: select your object, start up the uv texture editor and choose polygons > unitize. this process sets each face to fill the full uv space. in hypershade create a surface shader and click on the map button next to the out color attribute. add a ramp an set type to box ramp, interpolation to none and delete the middle color. move down the top color marker a bit down. go for a render and be surprised. here a possible result using the beloved raygun, my first maya model in nicely wireframe shaded:
so you’ve got three choices to fulfill this task – enough to keep you busy experimenting with the settings and find your own preferred way to deal with rendering wireframes.