P117 Digital Preservation of Sarawak Islamic Heritage via 3D Scanning: Technical Pipelines and Methodologies
Abstract
This paper presents an academically rigorous, multi-layered digital preservation framework designed for tangible cultural heritage, utilizing a proposed case study of historic Islamic cemeteries (specifically focusing on batu nesan or Jawi-inscribed tombstones) in Kuching, Sarawak. Tangible architectural assets and epigraphical records globally face accelerating degradation caused by tropical weathering, biological colonization, urbanization, and vandalism. Traditional documentation methods—such as subjective hand-drawing, standard photography, or invasive chemical molding and charcoal rubbings (frottage)—are either metrically insufficient or cause physical wear on fragile stone matrices. To establish an objective, contactless, and permanent archival record, we outline a paradigm shift from static 3D models to dynamic, Heritage Building Information Modeling (HBIM)-based Digital Twins (Akyol & Avci, 2025; Devetaković & Djordjević, 2022).
Our geomatic capture methodology evaluates the optical performance of Terrestrial Laser Scanning (TLS) phase-shifting sensors against Structured Light Scanning (SLS) systems (Arias et al., 2022; Tenschert et al., 2018). Crucially, we address the optical limitation of laser-based ranging on polished, crystalline stone surfaces (such as marble and granite), where subsurface scattering and reflection generate significant depth measurement bias and geometric noise, obscuring sub-millimeter engravings. We propose the deployment of high-resolution blue LED Structured Light Scanning (SLS), achieving a 3D point resolution of up to 30 µm to capture fine calligraphic details contact-free.
To decipher heavily weathered or eroded inscriptions, we apply Morphological Residual Models (MRM) as a trend-removal mathematical filter on reconstructed meshes (Pires et al., 2015). MRM isolates micro-relief surface details (residuals) from the backdrop geometry and renders them as distinct, color-coded vertex attributes. We then integrate these color-coded datasets into a Virtual Polynomial Texture Mapping (V-PTM) workspace. This allows epigraphists to use an interactive Reflectance Transformation Imaging (RTI) viewer to simulate virtual light domes and sweep raking light across the color-coded inscriptions, resolving overlapping strokes and recovering illegible texts.
Finally, we describe a fabrication pipeline to translate these digital twins into physical, scaled didactic resources using multi-material Fused Deposition Modeling (FDM) 3D printing (Arias et al., 2022). By employing polylactic acid (PLA) for the model and water-soluble polyvinyl alcohol (PVA) for the support structures, the fragile physical Jawi reliefs are preserved from structural wear during chemical post-print cleanup. To support global collaborative research, we advocate for archiving finalized datasets in lossless Wavefront .OBJ and Stereolithography .STL formats under Creative Commons Attribution-NonCommercial (CC BY-NC) licenses in open-access library repositories (Groenendyk, 2013).
