Spatial tactile feedback can enhance the realism of geometry exploration in virtual reality applications. Current vibrotactile approaches often face challenges with the spatial and temporal resolution needed to render different 3D geometries. Inspired by the natural deformation of finger pads when exploring 3D objects and surfaces, we propose TactDeform, a parametric approach to render spatio-temporal tactile patterns using a finger-worn electro-tactile interface. The system dynamically renders electro-tactile patterns based on both interaction contexts (approaching, contact, and sliding) and geometric contexts (geometric features and textures), emulating deformations that occur during real-world touch exploration. Results from a user study \rr{(N=24)} show that the proposed approach enabled high texture discrimination and geometric feature identification compared to a baseline. Informed by results from a free 3D-geometry exploration phase, we provide insights that can inform future tactile interface designs.

There is a growing interest in sustainable fabrication approaches, including the exploration of material conservation and utilisation of waste materials. Particularly, recent work has applied organic myco-materials, made from fungi, to develop tangible, interactive devices. However, a systematic approach for 3D fabrication using myco-materials is under-explored. In this paper, we present a parametric design tool and a fabrication pipeline to grow 3D designs using the mycelia of edible fungi species, such as Reishi or Oyster mushrooms. The proposed tool is designed based on empirical results from a series of technical evaluations of the geometric and material qualities of 3D-grown myco-objects. Furthermore, the paper introduces an easy-to-replicate fabrication process that can recycle different organic waste material combinations such as sawdust and coffee grounds to grow mycelia. Through a series of demonstration applications, we identify the challenges and opportunities for working with myco-materials in the HCI context.