Sudha,

The option File --> Print and File --> Print to PDF are not meant to print a 3D photo of your design. These print a general overview of your design, which can include a 3D representation of your design in the same quality as you can see in the 3D preview window. Try Print to PDF to see what the result is. Print gives the same result, but printed on paper.

If you want to make a photo, click 3D view --> Create photo. In the window that opens, you can set the size of the photo you want to create. You can also move the slider to change the quality settings. Quality 0 (Q0) gives the same result as the preview window, Q3 gives a high quality, photo-realistic rendering of your design. Remember that the bigger you make the photo, and the higher the quality setting, the longer the program takes to calculate it.

Please read this information on how to make photos. Then try making a few small photos first, to see how it works.

I don't know why in the Page setup dialogue the Print 3D view is disabled.

Hans