Simulating Resist Slip-Casting

Why do we digitally simulate physical making?

Resist slip-casting was an earlier project we developed that expands traditional ceramic slip casting by using waterproof masks to selectively block a plaster mold's water absorption, enabling the creation of intricate 2.5D tactile textures from a single mold. However, the physical practice is inherently slow (constrained by multi-day mold-drying cycles) and hard to predict (as the opaque nature of ceramic slip conceals the forming clay from view).

To facilitate our own resist slip-casting practice, we built a GPU-accelerated web simulator that enables designers to test 2D mask designs in a real-time 3D environment before committing to physical materials. We iteratively developed a resist slip-casting algorithm based on 3D cellular automata; comparing simulated outcomes with their physical counterparts. We also used the digital environment for rendering contour and surface normal maps to reveal nuanced surface qualities.

Rather than chasing absolute scientific accuracy, we built this simulator through a reflective Research through Design process. Through the process of developing and using it, we reflect on what simulators simulate, and critically—what they do not.

Ultimately, we argue that the simulator does not replace physical craft but adds to its repertoire. We therefore position simulators as a form of intermediate-level design knowledge, simultaneously formalizing tacit material knowledge into shareable tools, while also serving as a site for critical reflection on the relationship between digital and physical materials.

Authors
Clement Zheng
Han Bo

DIS 2026

Paper

Try the simulator

GitHub

Crafting Digital Ceramics

Rendering the invisible

The simulator visualized the formation of clay textures hidden under the opaque slip.

The simulator enabled 3D information to be rendered onto virtual materials.

surface normals

underside

surface contours

Refining mask patterns in the simulator to get sharper valleys.

Negotiating between the simulated and real

There is no instantaneous pausing of the actual casting process. Water, slip, and clay exists on a continuum based on their level of hydration rather than discrete entities as in the simulator. Actual cast textures tend to be a bit softer than the simulated counterpart and because thicker slip does not drain out and continues to accumulates in sharp corners.

Where we simulate making, and where we actually make.