You can achieve that effect too. For the hinge gap you need a 5-6 pixel wide gradient from black to transparent which is faded to be the shadow in the crease. I place the darkest line of the gradient right over the panel line to give it a little extra sharpness. The hardest part on the gradient is matching the slant of the line if it's not perfectly aligned N/S or E/W on the bitmap. This gradient layer should be pasted directly on to your bumpmap to see it shaded in 3D. Presto!
The rib detail is more tedious as the there are no parts that transfer from the color bitmap to the bumpmap. I shade all the fabric control surfaces a dark gray and erase where the ribs go. this gives the illusion of the fabric sinking into the gaps between the ribs. You want to use a soft eraser, but not too soft. have a 1 pixel blur transition from full gray to fully erased.
