You use the standard 3D Studio MAX Scale transforms to adjust a biped's posture by scaling the size of its links. You must be in Figure mode to scale the biped links. If you try to scale a biped without going into Figure mode, nothing happens.
As with Rotate, when you Scale biped links, Biped constrains the transform to use the link's Local coordinate system. The position of other biped links can change so they remain attached to the resized link. If you shorten the thigh, the calf and ankle will maintain their size, but change their position.
To scale a link, select the non-uniform scale icon from the Scale flyout on the Main Toolbar. When you select a body part to scale, use the Transform gizmo to scale along one axis at a time.
Tip: When you use Non-Uniform Scale to scale an object in 3D Studio MAX, a warning appears that the scale information is not contained in the Modifier stack. Turn on the checkbox in the warning dialog to disable it.
Use NU Scale and transform gizmo to scale links
If your character is symmetrical, select body parts in pairs and scale them at the same time. Select one body part and then choose Symmetrical in the Track Selection rollout. Now both are selected.
Or you can scale one and then use copy posture , and paste posture opposite from the Keyframing rollout. This is handy to insure symmetry in your character.
Tip: Use the PAGE UP and PAGE DOWN keys to move through your hierarchy as you work. Scale the thighs, then press PAGE DOWN to select the calves.
Scaling the biped limbs to fit snugly to the mesh will help when Physique is used to attach the mesh to the biped. The Bounding Box option uses biped limb dimensions to size the envelopes. This saves time when you adjust envelopes in Physique.
Rubber Banding Arms and Legs
Rubber Banding the Center of Mass