Well, "better" isn't really objective - for other purposes, "better" might mean lower polygon count.  And yes the modeling probably was done by different people, certainly there are enormous differences in the topology of the models - tons and tons of triangles in gen 3 models, none at all (apparently) in V4 - generally this is thought of as a better way to model, although it isn't such a big deal in Poser-land.

You are on the right track with a displacement map.  You can think of it as a bump map, only better - you can displace across polygon edges as Bill says, and together with the renderer's Smooth Polygons option, and the result is nice and organic-looking.  The layman-terms difference between bump mapping and displacement mapping is that bump mapping is a shading effect, that will not alter the geometry at all - while displacement mapping actually creates polygons ... and this will cost you render time, but it's a powerful and useful effect.

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