Now that we have our base mesh prepared, it is time for the fun. Let’s walk through the steps taken to develop this into a finished digital sculpture.

1. Block in Symmetrically




While our model is in the t-pose we should make a few large scale symmetrical modifications to things like the head, hands, feet, and basic planes of the body.

We refine the mesh to a first approximation, keeping in mind that most of the muscles, planes and shapes will change once the model is posed.

Once a body is posed the skeleton shifts,  muscles compensate, skin pulls, and gravity takes hold of everything – all significantly changing the forms. So just establish volumes and skeletal landmarks to guide you once the body is posed.

2. Pose



ZBrush gives us a selection of tools for taking our character out of the bind pose. Here I used a ZSphere rig to pose the character and subsequently refined it using TransPose.

To capture the weight and gesture of the pose a full IK rig would be ideal, but natively a ZSphere rig gives us a quick bind and the ability to interactively refine the pose by rotating the ZSpheres.

TransPose would also be a possibility, but it is best used for refinements. (Having to repeatedly remask and replace bones is time consuming when you are trying to match a pose exactly.) So with the ZSphere rig we get things close and then sculpt and TransPose from there.

3. Check proportions and adjust base mesh.




With the model posed, we want to recheck our proportions because our rig deforms imperfectly. Here we reestablish our landmarks by moving our base mesh back into position while looking at the edge-loops we put in for the points of the hips, the clavicles, the scapulae, etc. This gets us to a solid starting point for refining the volumes and each body part.

HINT: Remember the boney structure that is holding up the volume of the figure. Nowhere should the surface of the model violate the boney structure – e.g. the back and front of the model should all conform to the shape of ribcage and never appear to penetrate it. Any violations quickly destroy the impression of solidity in a model.

4. Refine proportions with TransPose



As the model progresses we invariably notice proportional mistakes that need to be corrected. (I noticed MANY of them during the refinement of this model, all the way up to the end.)

Create a new layer and use the TransPose tool to fix the problem. TransPose is one of the most powerful tools in ZBrush, so learn it well. You will use it often.

5. Locate landmarks



These solid reference points help us hang muscles on the figure.There are many places on the body where the skeleton is subcutaneous (underneath the skin). We locate these ‘landmarks’ first and then string muscles between them.

They give us confidence that we are placing the muscles from the correct origins to the correct insertions. (Things we investigated in our ecorche drawings!)

The movie above shows me locating the spine of the scapula -- a critical landmark on the upper back -- and then using that to guide the correct placement of the trapezius, rear deltoids, teres major, and other upper back muscles.

6. Sketching Muscles and Anatomy

Now to add muscles. Typically I sketch in the volume of the muscles using the clay tubes brush with a round alpha (#06) at the highest subdivision level.

I like the feel of the brush and the slow accumulation of volume is easy to control. Once the volumes are established, the hard edges are easily smoothed and transitions refined. Here is a selection of time-lapse movies that show the development of the different body parts and address some of the considerations specific to this sculpture.

Click to play a movie
A. Torso.mov
B. Arms.mov
C. Back.mov
D. Leg.mov
E. Forearm and Hand.mov

7. Assess Accuracy



Comparing the negative space and major angles of our digital sculpture (left) and the original reference shows that they are very close, though not perfect. But as they say, "Close enough for government work and computer graphics."

It is easy to fool yourself into thinking your model is accurate. You must stay alert and be ruthlessly objective when comparing your model to the reference.

If it “just doesn’t look right”, forget trying to fix details. Start checking the proportions (things like the ratio of the length of the forearm to the length of the upper arm, the lower leg to upper leg, etc) and then the pose.

Look closely at the angles between joints; use the negative space to help you here. If the balance of the pose is just a little off, it will throw off joint angles and distort the positive and negative spaces.

Rarely do misplaced muscular details ruin a model. Most often it is larger issues; likely one of the above. If the big shapes and angles are correct, your model will look good regardless of the fine details.

8. Add transitions

Once the pose, big shapes and muscle volumes are established with some degree of confidence, it is time to refine the transitional planes between muscle groups. This is the detail work.

If the muscles are blocked in well, this process is quick and generally involves working into your model with a fine brush, sharpening concavities or refining the shape of convexities.

It is like adding accents and highlights to a painting. They make the forms “pop”. (But not if the form is misshapen to start with, in which case they will not help at all – see 7.)