Mannequins are a feature built into Zbrush for rapidly creating humanoid character shapes, and posing them in a scene. They function similarly to a ZSphere armature. Mannequins are a great tool for artists to block in composition for scenes too.
Press comma ‘,’ to open the lightbox menu, then select Project, double click the Mannequin folder to see a list of mannequins, then select the one you want to start working on.
Select Move, Rotate or scale, then Click on a joint to move it, which will allow limbs to change length, shape etc. Holding the Ctrl key will stop limb distortion from happening, and the joint will merely rotate.
(You can move the whole model around the scene by Ctrl + Clicking the root Zsphere at the character’s hip. )
Click between joints to let you rotate them into place using forward kinematics.
Hold the Alt Key and click a joint to move the joints below AND directly above it, which can be useful for certain poses.
The easiest way to rotate a mannequin is to go to the Deformation palette and adjust the rotate slide (taking care to check the correct axis first.) This can also be used to scale or resize the model.
Go into draw mode and click between two joints to add an extra joint. This can be used along with scaling etc to turn a humanoid base into a more alien one.
Press A to switch between Armature mode where you can pose the mannequin and Adaptive Skin Mode, where you can sculpt on the model. You can flip between modes, repose as necessary then get back to sculpting.
You can clone your mannequin by clicking Duplicate in the Subtools palette, then Ctrl + clicking to move it away from teh original and into position.