Vasquez - the mat spheres sort of tells Poser that the stuff INSIDE is to be affected/deformed when limbs are bent etc., and the stuff OUTSIDE is not. Try loading a figure, starting up the joint editor, choose a limb and check under body parts. Select every element in turn (yes, try the mat sph.s, too), and change their values SLOWLY via the dials. It's very instructive - just be sure to set the display to rendered-all-the-time (not switching to boxes when moving). That way you will quickly develop an intuitive understanding of what happens. Just remember - whatever you do DON'T SAVE THE FIGURE !!!!!