eyeGrey
item2a
item5a

Perspective view in grey tone.(rollover for alternative)
Cost around 70

Cross-section in grey tone.(rollover for alternative)
Cost around 60

Elevation view in black line and grey tone
Cost around 45

Linework illustrations with tints and tones of flat monochrome colour or greyscale added to give interest and form or to fulfil a design requirement.

This is a relatively simple process, on this image, and does not add too much to the overal cost from the initial line work version.