pARam: Leveraging Parametric Design in Extended Reality to Support the Personalization of Artifacts for Personal Fabrication

Abstract

Extended Reality (XR) allows in-situ previewing of designs to be manufactured through Personal Fabrication (PF). These in-situ interactions exhibit advantages for PF, like incorporating the environment into the design process. However, design-for-fabrication in XR often happens through either highly complex 3D-modeling or is reduced to rudimentary adaptations of crowd-sourced models. We present pARam, a tool combining parametric designs (PDs) and XR, enabling in-situ configuration of artifacts for PF. In contrast to modeling- or search-focused approaches, pARam supports customization through embodied and practical inputs (e.g., gestures, recommendations) and evaluation (e.g., lighting estimation) without demanding complex 3D-modeling skills. We implemented pARam for HoloLens 2 and evaluated it (n=20), comparing XR and desktop conditions. Users succeeded in choosing context-related parameters and took their environment into account for their configuration using pARam. We reflect on the prospects and challenges of PDs in XR to streamline complex design methods for PF while retaining suitable expressivity.

Figures (16)

• Figure 1: Overview of the process and functionalities supported by pARam. pARam enables in-situ interaction with parametric designs for personal fabrication (a). Relying on extended reality headsets facilitates in-situ previewing, but also input support like direct measurements (b) or estimation components that rely on the scanned environment mesh (c). Our implementation of pARam focuses on steps 2 to 6 primarily, but covers the entire pipeline.
• Figure 2: Basic elements of pARam's user interface. A 2D UI (a) provides buttons to toggle all input and estimation modes and displays all parameters with a name, a slider, and a value display. A 3D model preview (b) allows the user to position the object in space and manipulate handles, depicted as blue spheres, to control individual parameters directly.
• Figure 3: As an addition to slider-based interactions, pARam lets users directly manipulate aspects of the model that are described by parameters, as an alternative to the 2D UI (1). Users can grab the spheres to change associated parameters (2). A direction hint is shown for parameters linked to an axis (2, top right). After letting go, the respective parameter is updated in the UI (3). Multidimensional parameters (e.g., positions), can be altered in a similar fashion (4).
• Figure 4: For parameter manipulations, pARam allows users to temporarily ignore validity constraints (1), where the armrest protrudes beyond the seat, but restores a valid state of the model as soon as the user ends their interaction (2), with the model visibly snapping back to a valid state.
• Figure 5: pARam provides 2 modes for gesture-based measuring: one-handed (a), where the distance between index finger and thumb is used, and two-handed (b), where the distance between index fingers is taken. This feature can be used as a reference, or as a direct input to a parameter chosen previously. To leave the hands free for such measurements, pARam provides voice interactions (c). Users can first point at a parameter to change, say "measure this" (1), move their fingers to the desired distance, and say "take measure" (2) to transfer the current value to the previously chosen parameter (3)