Hierarchy of Forms Part 2: The Rhythm of the Mesh (Secondary Shapes)
Once you have established the Primary Shapes (The Silhouette), you might notice a problem: Your character looks solid, but "... ...;stiff." They look like a mannequin made of separate block-mesh pieces.
This is where Secondary Shapes come in. This stage isn't about muscles or cloth folds yet; it is about Rhythm and Gesture.
The Problem: "The Sausage Link Effect" A common mistake Juniors make is treating anatomy like a medical diagram. They sculpt a bicep, then a tricep, then a deltoid, and paste them together like sausages. The result is a character that looks anatomically "correct" but completely robotic.
The Solution: Flow Over Anatomy Senior Artists don't just sculpt muscles; they sculpt Movement. Secondary forms are the bridges that connect your Primary Shapes.
The S-Curve: Organic things rarely move in straight lines. Your forms should flow in "S" curves across the body. The curve of the shin should flow into the opposite curve of the thigh.
Insertion Points: Don't just place a muscle on top of the bone. Show where it tucks in. The Latissimus Dorsi doesn't just sit on the back; it twists and flows into the armpit.
Gravity: Even in a T-pose, weight exists. Secondary shapes should show the effect of gravity (flesh sagging slightly, cloth creating tension points).
The Technique: The Clay Polish Test In ZBrush, if you run a "Clay Polish" or a slight smooth, does your character still look energetic? If smoothing the mesh makes it look boring, your Secondary Shapes were weak. Your goal is to make the surface feel tensioned, like a coiled spring, before you ever add a pore or a wrinkle.
Rule #2: Don't model anatomy. Model the energy of the anatomy.
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