Building creatures in ZBrush
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.
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.
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.
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.
It was then time to start building up the underlying tissue and fatty deposits. Depending on the nature of the character I'm trying to create I'll spend a lot of time with the selection of clay brushes and build up the deepest crevasses. I'll then add larger secondary forms to areas of compression under the arms and between the legs while building the forms to support suggested anatomy, such as mouths, ears and eyes.
My muscle and bone SubTools were kept in the model as I developed the sculpt so I could refer back to them while placing new forms.
ZRemesher and projection
Before I start applying the smallest forms or micro details, I like to produce a well organized and ready-to-go mesh. This helps to optimize the polygon flow and apply the details with little or no distortion, which can occur when applying them over an oddly stretched polygon layout. I duplicated my work to allow me to project back onto the new mesh. ZRemesher does a great job every time.
If I'm looking for more control over the flow, especially around the mouths or eyes, I will use the ZRemesher Guide brush to force the polygon flow into a direction I prefer, simply by drawing guides directly onto the mesh.
After ZRemesher and projecting, I took some time to review several areas like the hands, feet and face, to refine the sculpt, and do any clean up from errors that may have occurred during the projection.
This was good time to push all the forms a little further too, so that they could hold the details I apply in the next steps. I added volume and weight to the larger wrinkles with the Inflate, Clay and DamStandard brushes, which gave some reason behind my choices in placing the original forms. I tried to hit every area and bring the whole figure up to the next level. This stage took some time, but it was absolutely worth it to get as much out of concept as possible.
I like to use custom alphas for each character I create in Photoshop. Making my own helps to bring another layer of originality to my work, while making each of the characters unique from one another. Skin details, scars and imperfections add another level to the story I want to tell and gives my Red Sands characters the look of a life well-lived. I added these details after creating a HD subdivision level; mixing bumps, pores and micro wrinkles to achieve the illusion of skin.
I essentially apply diffusion no matter what the alpha. When I work at such a small scale, it will affect my specular highlights during renders so I checked the model from a distance by zooming out and changing the lights.
Polypainting is one of my most favorite parts of a project. The character is fully formed and ready to be given a push over the edge of realism with a splash of color.
I use many techniques to apply Polypaint, from projected textures with spotlight, to straight hand painted touches using the many masking options within ZBrush. Being flexible and experimental generally provides my best results. Sometimes I'll work through the subdivisions from low to high applying color with the spray stroke and alpha 22. It blurs and builds some nice variations in patterns and color intensity.
Using color is great, but creating skin patterns or markings of some type help to enhance the impression the character will leave. So I did some research and added a little extra where necessary.
The fibre system in ZBrush allows for additional touches that really push the realism. I used them to spread fine hairs across the surface of my sculpt, and to create the large hairs and quills on Thill's back. Although the smaller hairs were not useful when exporting my characters to be milled 5' tall, for the painting and design work it added a great deal of appeal.
I tested all my fibres on a simple sphere and saved them out to become personal hair presets. I found it better to adjust all my settings before applying them to my character as it was much quicker to test and adjust at that time.
Posing and variation
Posing is entirely story-driven and made with a narrative in mind. I began by adjusting the trunk using the hips as an anchor. I followed with the chest, legs and arms, moving outward toward the extremities. Transpose Master is my tool of choice for any project with a great number of SubTools, and as the adjustments become finer, I revert back to using simple masking and the transpose action line.
Rendering and compositing
For me, the shift from sculpting to rendering out a scene is a jarring one. To keep things rolling I'll often build a ZBrush studio scene using a polysphere to predefine the light caps, materials and BPR settings with its filters. I have several studios saved out as projects where I can start a sculpt or import a sculpt, so it becomes a matter of minor lighting and filter changes to achieve a good result. In the case of Thill I started in a premade studio and as the sculpt evolved I made changes to the shadow, AO, blur depth, lighting intensities and their color.
A good final painting relies on getting a good render so I spent time producing the best one I could in the time I'd blocked out for myself. Breaking the render into additional passes, separating lights, color, depth, spec highlights etc, gave me more flexibility when doing the final composite. As a student of theatre, I also like to add an element of texture and grit back into the render using photos as well as several painting passes by hand to bring the final design images to a close.
I did small renders first with a low sub pixel setting, and made sure I was happy before cranking up the document size and sub-pixel depth to my machine's max and committing it to an evening of chewing out a render. Most of my renders take overnight or longer to complete. When it was complete, I exported the document along with all the BPR passes.
Accessories include elements of scenery, additional characters, weapons, gear and bases. Each one is added to enrich the story and fill out the scene. I spend as much time designing these elements as I do creating a character in many cases. Most are destined for the milling machine and full scale reproduction along with the character, so they need to hold up in terms of design aesthetic and quality.
Thill; the final character placed in a scene.
Take a peek at the finished sculpts in Cameron Farn's sculpture collection on his website
Interested in one of Cameron's favorite parts of the process? Try our polypainting tutorials
Like to learn more about creature creation in ZBrush? Take a look at our best-selling books