Cameron Farn reveals the ZBrush pipeline used in designing his large scale physical sculptures…
I usually start with a sphere, but it can be any primitive converted into a PolyMesh3D. I filled it with black and set it on a light grey background. Using various brushes such as the Move brush I pushed, pulled and warped the sphere into as many alien-looking body forms as possible, adding limbs and heads by duplicating the previous sphere or appending another. Once I'd found an exciting form I merged the spheres together into one SubTool and gave it a cool name.
As a tip, you should absolutely shred the polygons with this technique. Resist the urge to DynaMesh until you have a full figure, the hard edges of the overstretched polygons can give the form a nice read.
Silhouettes are used to create form in the absence of detail and bring focus to the iteration process
Having a good silhouette was a great start; it was then time to determine whether the form I created could support a skeleton. I inserted another sphere, filled it with an off-white, and used it to recreate each bone from various references. I placed each bone within the form to support aspects of limb-hinging, skull shape and organ packaging.
This is a non-destructive way of exploring whether the character, as it is represented by the silhouette, can stand, walk and move in the way I imagine. As the skeleton is built with function as a leading principle it began to tell me where and by how much the outer form needed to change.
Bones - everything hangs on them, including the success of a character
The first render test for the bones. ©2014 Cameron Farn
The skeletal system brought me closer to understanding how this character would function. I then looked at the muscular system to capture and hold it all together and added the underlying forms that would ultimately affect its final look. Using another appended sphere and filling it with a red value, I started to lay out the muscle systems, supporting my choices with references, and concentrating on range of motion, physique and function.
Bulking up the character to add function behind the form
A render test for the muscle. ©2014 Cameron Farn
Generating the skin
With the bone and muscle established under the surface I could then generate a more accurate skin. It was unlikely that the live silhouette had the topology to hold the next stage of forms, given how much it had been shredded and reorganized by DynaMesh.
To incorporate the illusion of skin thickness and other tissues or fatty deposits I needed to generate a new watertight skin to work from. I saved out my muscle system and merged the original with the skeletal system. I used the Unified Skin function to generate a suitable mesh and projected it over the muscle and skeletal forms to begin sculpting.
After I generated the unified skin I auto-grouped the SubTool and looked for loose parts I hid those I found and used the delete hidden button under Geometry/Modify Topology.
Generating the skin to prepare for the sculpting process