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Augmented Carpentry: Computer Vision-assisted Framework for Manual Fabrication

Andrea Settimi, Julien Gamerro, Yves Weinand

TL;DR

Augmented Carpentry (AC) introduces a computer vision–assisted, open-source framework that retrofits ordinary woodworking tools with sensing and AR guidance to support manual timber fabrication. It combines toolhead pose estimation with a timber-centric SLAM (T-SLAM) and a digitally locked execution model to provide real-time overlays and a 3D recording of fabrication decisions, enabling human–computer collaboration without rigid workflow enforcement. In a 1:1-scale experimental campaign (166 joints across 57 spruce beams), AC achieved mean joint-position errors below 3 mm, sub-millimeter joint-face accuracy, and drilling angles around 1.2°, with some degradation for beams longer than ~3 m due to map quality. The work demonstrates a path toward democratizing digital timber fabrication by retrofitting existing tools, reducing reliance on high-end robotics, and enabling traceable, on-site fabrication workflows that integrate human skill with digital guidance.

Abstract

Ordinary electric woodworking tools are integrated into a multiple-object-aware augmented framework to assist operators in fabrication tasks. This study presents an advanced evaluation of the developed open-source fabrication software Augmented Carpentry (AC), focusing on the technical challenges, potential bottlenecks, and precision of the proposed system, which is designed to recognize both objects and tools. In the workflow, computer vision tools and sensors implement inside-out tracking techniques for the retrofitting tools. This method enables operators to perform precise saw-cutting and drilling tasks using computer-generated feedback. In the design and manufacturing process pipeline, manual fabrication tasks are performed directly from the computer-aided design environment, as computer numerical control machines are widely used in the timber construction industry. Traditional non-digital methods employing execution drawings, markings, and jigs can now be replaced, and manual labor can be directly integrated into the digital value chain. First, this paper introduces the developed methodology and explains its devices and functional phases in detail. Second, the fabrication methodology is evaluated by experimentally scanning the produced one-to-one scale mock-up elements and comparing the discrepancies with their respective three-dimensional execution models. Finally, improvements and limitations in the tool-aware fabrication process, as well as the potential impact of AC in the digital timber fabrication landscape, are discussed.

Augmented Carpentry: Computer Vision-assisted Framework for Manual Fabrication

TL;DR

Augmented Carpentry (AC) introduces a computer vision–assisted, open-source framework that retrofits ordinary woodworking tools with sensing and AR guidance to support manual timber fabrication. It combines toolhead pose estimation with a timber-centric SLAM (T-SLAM) and a digitally locked execution model to provide real-time overlays and a 3D recording of fabrication decisions, enabling human–computer collaboration without rigid workflow enforcement. In a 1:1-scale experimental campaign (166 joints across 57 spruce beams), AC achieved mean joint-position errors below 3 mm, sub-millimeter joint-face accuracy, and drilling angles around 1.2°, with some degradation for beams longer than ~3 m due to map quality. The work demonstrates a path toward democratizing digital timber fabrication by retrofitting existing tools, reducing reliance on high-end robotics, and enabling traceable, on-site fabrication workflows that integrate human skill with digital guidance.

Abstract

Ordinary electric woodworking tools are integrated into a multiple-object-aware augmented framework to assist operators in fabrication tasks. This study presents an advanced evaluation of the developed open-source fabrication software Augmented Carpentry (AC), focusing on the technical challenges, potential bottlenecks, and precision of the proposed system, which is designed to recognize both objects and tools. In the workflow, computer vision tools and sensors implement inside-out tracking techniques for the retrofitting tools. This method enables operators to perform precise saw-cutting and drilling tasks using computer-generated feedback. In the design and manufacturing process pipeline, manual fabrication tasks are performed directly from the computer-aided design environment, as computer numerical control machines are widely used in the timber construction industry. Traditional non-digital methods employing execution drawings, markings, and jigs can now be replaced, and manual labor can be directly integrated into the digital value chain. First, this paper introduces the developed methodology and explains its devices and functional phases in detail. Second, the fabrication methodology is evaluated by experimentally scanning the produced one-to-one scale mock-up elements and comparing the discrepancies with their respective three-dimensional execution models. Finally, improvements and limitations in the tool-aware fabrication process, as well as the potential impact of AC in the digital timber fabrication landscape, are discussed.

Paper Structure

This paper contains 18 sections, 3 equations, 24 figures, 1 table.

Figures (24)

  • Figure 1: Users experienced the proposed AR-based guiding system for enhanced woodworking during an organized public workshop. Shown are a user utilizing an AC setup for saw cutting (back view) and another interacting with a touch display for augmented-guided drilling (front view).
  • Figure 2: Overview of the designed hardware set-up mounted on a miter saw and once detached: (a) the monocular RGB camera, (b) magnetic clip for the onboard sensor and interface, (c) touch display, (d) two articulated arms for the camera and display, (e) protective case with belt clip, (f) battery adapter, (g) power tool 18V battery, (h) , (i) mounted tool head, (n) 3D-printed power tool's mount adapted to each power tool model.
  • Figure 3: resuming the controls to input and refine the toolhead pose: (a) rough projection of the selected toolhead, (b) library of selectable toolhead models, (c) currently selected toolhead, (d) machine-refined toolhead position and orientation, (e) confirming the pose, (f) stopping the refiner, (g) reloading the latest saved pose, (h) hiding the 3D model silhouette widget, and (i) resetting the pose to the default value. The user can input the 3D model transformation matrix single values by interacting with six sliders, each representing the model translation axis x (l), y (r), z (p) or the object rotation through axis x (l), y (o), or z (n).
  • Figure 4: s embedded in files loaded together with each entry of drill bits, chainsaw bars, and circular saw blades in the toolhead library of : drill bit (a) base, (b) chuck, (d) eating, and (e) tool tips; chainsaw bar (f) base, (g) normal, chainsaw (h) start, mid and end points; circular saw blade (i) center, (r) normal and (p) radial point. It is worth noting that (t) labels are incorporated as edges to supply additional edge data for the pose detector when possible.
  • Figure 5: Close-up of a tag stripe. Each fiducial marker features a unique pattern that makes it unequivocally identifiable. Each stripe measures approximately 1 m in length, can hold 47 tags, and contributes to 474 unique stripes.
  • ...and 19 more figures