Digital Sculpting Process
From Concept to Block-up
In photoshop, my concept art is scaled to the desired jewelry size based on a grid that is true to Scale 1 in ZBrush. The combined grid/concept *.png is then imported into ZBrush for use as reference while blocking out the basic, low-poly form. (a shout out of thanks to “Riz” for use of his grid & guidance in setting project scale)
ZBrush Custom UI
ZBrush UI, customized for jewelry design courtesy of Tomas Wittlesbach, Founder & Instructor of ZBrush Jewelry Workshop
A highly customized ZBrush user interface helps to stream-line all of the processes involved in taking a design from beginning to finished form as a useable file for 3d printing. Here, the canvas shows my reference art visible through the active portion of my multi-mesh model.
From Block-up to High-resolution Detail
The low-poly block-up is sub-divided many times. Each subdivision level creates a multiple of four, with each polygon extremely tiny. While the resulting mesh can amount to millions of polygons and a very large file size, this is what is needed for sculpting fine details.
When a digital model is destined for 3d printing, wall thickness must be taken into account. Minimum wall thickness is the smallest possible thickness a model can have while maintaining its structural integrity. Minimum wall thickness is dictated by the 3d printer being employed. Many require a 1.5 mm minimum, with the absolute minimum for others being 0.6 mm. While sculpting, I measure areas where wall thickness may be an issue, and adjust those areas so that they do not fall below 0.6.
Watertight Decimated Sculpt Ready for 3d Printing
Left: close-up image of my Trumpet Flower pendant after decimation to 250k polygons
Right: 3d render of my Trumpet Flower pendant in sculptor’s Mah-dirty-blue material
To take the *.stl file into any 3d printing software it is first necessary to decimate the mesh (reduce the level of detail without significantly changing the way it looks) . Once decimated, for a 3d print to be successful it must also be checked for water-tightness (no holes in the mesh).
Post-design Process
Still on their support structures, these 3d resin prints were based on the decimated *.stl file of my Trumpet Flower pendant and fancy bale. The details came out very well, though it would have been preferable to have the supports concentrated on the pendant’s back side.
I have had my designs 3d printed in both castable resin and high-precision wax. In my experience, castable resin prints are unreliable in the lost wax casting process (also known as investment casting). This is in contrast to molds made from wax and even organic materials, both of which yield very accurate and reliable results. For this reason my recommendation would be a 3d high-precision wax print. Further, for repeat castings, due to both 3d resin print and resulting investment mold having to be replaced for each and every cast, I would recommend that the 3d high-precision wax print be used to create a reusable mold.
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