This is by far one of the oldest stretching topics in 3D graphics, as it goes back to the roots of what people have been trying to achieve in cinema since it’s inception. Prior the the fairly recent insurgence of 3D we’ve seen in the last 20 years with large portions of what was previously either live acted or practical effects in film.
So why did I name the post progression via regression? Well the technical aspect of ‘digital sculpting’ as it’s existed till quite recently has tended to outweigh flat artistic merit, in the sense that using more traditional techniques transferable from mediums such as clay or marble sculpture.
Back in the dark ages (or the renaissance, depending how you look at it) known as the 90s the prospect of such an application was only a thing of dreams (well, it was in development). We were just starting to see Pixar produce feature 3D film in a fashion in a fashion that would be taken seriously. It’s during this time as well that we see the rise of the now very standardised NURBs and subdivision pipeline that we still use prominently in 3D modelling today. This is still integral to the knowledge base of any 3D artist of course, but if your primary concern is 100% to get something that LOOKS the bill, outside of the work that needs to be done later to get models functioning for animation topology or efficiency, then it becomes a somewhat cumbersome and deliberate process that is a skill set unto itself and more traditional techniques can’t be brought to the table.
One of the first examples of a more traditional sculpting application, ZBrush is introduced at the 1999 SIGGRAPH conference in Los Angeles. Offering the ability to manipulate a dynamic mesh in a manner simulating tools more traditional to a sculpting background. On a similar vein and the main competing program is Mudbox, developed initially by Skymatter, a studio founded by Tibor Madjar, David Cardwell and Andrew Camenisch, formerly artists in the direct employ of WETA digital (yes, that WETA) and first used to produced assets for Peter Jackson’s 2005 rendition of King Kong. Mudbox has since been bought by Autodesk and integrates near seamlessly with their their software.
These work on a very similar workflow to that of a clay sculpt. If I was to use zbush as an example:
1. Reference and Roughing Out
As with most artistic endeavors, the first thing you should do is acquire and set up appropriate reference material. Most 3D suites offer the ability to have you reference directly in the scene and ZBrush is no exception.
What ‘roughing out is referring to is much like what you can see if the ZBrush image on the right. In traditional sculpting this would be your initial shaping of the core piece of clay you’re using with your hands. At this stage you’re not aiming for details, just to get a rough shape in place that you can work detail into on a much smaller scale later. In a program like ZBrush you’d make good use of your scale and move tools here; they become your hands, as such.
2. Adding, removing and maneuvering
When presented in a traditional fashion your sculpting tool kit will incorporate a wide variety of knives, sticks, brushes, wires etc. Basically any physical object can give a different effect when manipulating your clay. As you refine your model as well sections of that clay may need to be removed volumetrically from sections or require new clay added to build upon the rough foundations. In reality, this involves physically adding more clay.
In ZBrush, there’s a brush for that.
3. Cutting and re-positioning
Prior to any small details to be added it might be required to shift something as large as an arm from it’s foundations to a new position. In a physical sense you’d use a knife to slice wet clay away and then rejoin it elsewhere to your model (might only be a cm or two).
In ZBrush you can mask off whole sections of a model to be moved, adjusted or deleted all-together. Alternately, any major geometric divides, such as a limb, can be listed as their own subtool, either from inception or using the aforementioned technique, and be treated as a separate model for the sake or position adjustment, which still treating any overlapping geometry as the same surface for smoothing.
The end of your workflow as far as the sculpt itself is concerned, detailing to a traditional model is either a matter of getting in very close with concise tools, though if you’re looking to repeat detail in a more uniform fashion you may also employ ‘pressing’ – the act of pushing a mould into the clay to indent it uniformly, or ‘strigging’ – using an indented mould to fashion your detail from a more malleable material, such as plaster, then attaching that to the main model by pressing it to the wet clay.
In ZBrush, you can use your brushes set very small to eek out small details in much the same way, and your pressing and strigging comes from using custom stroke, alpha and texture brushes, as illustrated in the video below.
Comparing Traditional and Digital Sculpting (Sculpting Concepts) (Digital Sculpting with Mudbox). (2016). What-when-how.com. Retrieved 17 May 2016, from http://what-when-how.com/digital-sculpting-with-mudbox/comparing-traditional-and-digital-sculpting-sculpting-concepts-digital-sculpting-with-mudbox/
Holland, P. (2016). Clay Sculpture Technique – An Introduction. Figurines-Sculpture.com. Retrieved 17 May 2016, from http://www.figurines-sculpture.com/sculpture-technique.html
Mahon,. (2011). Digital sculpting vs. traditional sculpting • Chest of Colors. Chest of Colors. Retrieved 17 May 2016, from http://chestofcolors.com/digital-sculpting-traditional-sculpting/
Polygons to NURBS. (2016). Retrieved from http://www.3dtutorialzone.com/Polygons_To_NURBS/1.jpg
Raitt, B. & Minter, G. (2016). The Minters. Theminters.com. Retrieved 17 May 2016, from http://www.theminters.com/misc/articles/derived-surfaces/index.htm