Researchers can build craft-aligned digital fabrication technologies by designing interfaces inspired by craft tools. This process often demands real-time physical interactions not supported by today’s automation-focused CNC control systems. We theorize we can lower engineering challenges for craft-aligned CNC prototyping by allowing designers to modify existing CNCs to support both automated and real-time control. We contribute a new creative motion control system, Stepdance, which consists of two elements: 1) modular controllers that replace the G-code controller of a CNC and can be chained together to develop new interfaces, and 2) a modular programming library that supports declarative mappings between live user input, pre-programmed operations, and machine motion. We developed Stepdance with practitioners at the Haystack Mountain School of Craft, where we used the system to modify commercial plotters and 3D printers. We analyze the resulting artifacts, interactions, and ideas to discuss how Stepdance can broaden the practice of CNC design via physical metaphor.

Ceramics practice is an embodied activity where creators use manual tools in unique ways to shape physical material. Clay 3D printing uses the same material as manual ceramics craft, enabling new opportunities for form and texture by precisely controlling the 3D printing toolpath. However, current clay 3D printing design workflows require developing forms through digital software rather than tool-based making. We present Clay ARtools, an augmented reality (AR) system for designing clay 3D printed vessels. We developed Clay ARtools in collaboration with a professional ceramicist to create AR toolpath editing operations that reference manual use of ceramic tools. Through the design and fabrication of 3D-printed clay artifacts, we demonstrate how AR ceramic tools enable precise and controllable modifications of the toolpath, from the overall form down to individual toolpath points. We demonstrate how extending physical tool metaphors with digital representations and numerical precision enables craft-like interaction with CAM-based design techniques.

pattern viewer re-assembly plan pattern library 1. undo seams 3. add yellow tiles 2. rotate front left leg right leg tank top shorts back Making a first garment Wearing the garment Second garment Re-using tiles to make a second garment 20 tiles 30 assemblies 2 hr 30 min 4 hr 40 min 32 tiles 56 assemblies 37 tiles 65 assemblies 5 hr 25 min 3D-printed connector and assembly technique easy and risk-free disassemblyFigure 1: texTile is a workflow for modular tile-based garment construction within the crochet granny squares technique.The texTile workflow supports making and re-making garments by re-using crochet tiles.We develop this workflow by leveraging tools from computational fabrication and computational design.We design a non-permanent assembly technique using 3D-printed connectors, and a software tool with a pattern library, pattern viewer and re-assembly plan.

The ability to represent artworks as stacks of layers is fundamental to modern graphics design, as it allows artists to easily separate visual elements, edit them in isolation, and blend them to achieve rich visual effects. Despite their ubiquity in 2D painting software, layers have not yet made their way to VR painting, where users paint strokes directly in 3D space by gesturing a 6-degrees-of-freedom controller. But while the concept of a stack of 2D layers was inspired by real-world layers in cell animation, what should 3D layers be? We propose to define 3D-Layers as groups of 3D strokes, and we distinguish the ones that represent 3D geometry from the ones that represent color modifications of the geometry. We call the former substrate layers and the latter appearance layers. Strokes in appearance layers modify the color of the substrate strokes they intersect. Thanks to this distinction, artists can define sequences of color modifications as stacks of appearance layers, and edit each layer independently to finely control the final color of the substrate. We have integrated 3D-Layers into a VR painting application and we evaluate its flexibility and expressiveness by conducting a usability study with experienced VR artists.

We present an interactive system to ease the creation of so-called video doodles - videos on which artists insert hand-drawn animations for entertainment or educational purposes. Video doodles are challenging to create because to be convincing, the inserted drawings must appear as if they were part of the captured scene. In particular, the drawings should undergo tracking, perspective deformations and occlusions as they move with respect to the camera and to other objects in the scene - visual effects that are difficult to reproduce with existing 2D video editing software. Our system supports these effects by relying on planar canvases that users position in a 3D scene reconstructed from the video. Furthermore, we present a custom tracking algorithm that allows users to anchor canvases to static or dynamic objects in the scene, such that the canvases move and rotate to follow the position and direction of these objects. When testing our system, novices could create a variety of short animated clips in a dozen of minutes, while professionals praised its speed and ease of use compared to existing tools.

We propose a method to transform unstructured 3D sketches into piecewise smooth surfaces that preserve sketched geometric features. Immersive 3D drawing and sketch-based 3D modeling applications increasingly produce imperfect and unstructured collections of 3D strokes as design output. These 3D sketches are readily perceived as piecewise smooth surfaces by viewers, but are poorly handled by existing 3D surface techniques tailored to well-connected curve networks or sparse point sets. Our algorithm is aligned with human tendency to imagine the strokes as a small set of simple smooth surfaces joined along stroke boundaries. Starting with an initial proxy surface, we iteratively segment the surface into smooth patches joined sharply along some strokes, and optimize these patches to fit surrounding strokes. Our evaluation is fourfold: we demonstrate the impact of various algorithmic parameters, we evaluate our method on synthetic sketches with known ground truth surfaces, we compare to prior art, and we show compelling results on more than 50 designs from a diverse set of 3D sketch sources.

We present CASSIE, a conceptual modeling system in VR that leverages freehand mid-air sketching, and a novel 3D optimization framework to create connected curve network armatures, predictively surfaced using patches with C0 continuity. Our system provides a judicious balance of interactivity and automation, providing a homogeneous 3D drawing interface for a mix of freehand curves, curve networks, and surface patches. Our system encourages and aids users in drawing consistent networks of curves, easing the transition from freehand ideation to concept modeling. A comprehensive user study with professional designers as well as amateurs (N=12), and a diverse gallery of 3D models, show our armature and patch functionality to offer a user experience and expressivity on par with freehand ideation, while creating sophisticated concept models for downstream applications.