It's very quick (a few seconds) to add bevel to a shape in Photoshop but when I do the same for a graph object in Illustrator the Mac I'm working on takes an age to render the artwork. Why does this happen?
Photoshop uses raster shading to create a pseudo-3D appearance of a bevel and emboss. Basically it just puts a light color at one angle and a dark color at an opposite angle, but Photoshop does not alter the original object.
Illustrator uses 3D extrusion and lighting to create any bevel. This means it must plot the object boundaries and then apply extrusions to the shapes, then apply lighter and darker colors tot eh extrusions. 3D rendering simply takes more time to processes. Illustrator's 3D effects have always been horribly slow as well.