PBR (no not that one)

One of the key challenges to the visualisation of 3D reality-capture data has long been how it is presented to those viewing and using it. Within heritage and archaeological study, capturing accurate geometry and diffuse colour texture is traditionally the focus here, with every effort taken to ensure the finished dataset resembles the subject as closely as possible. That takes care of the input. However, the output is a separate challenge. Rendering it accurately depends on the subject and its material, and to what ‘level of detail’ you need to convey; this can completely influence how we see and interpret the artefact or site. In a lot of circumstances where we view these models, we accept that in most cases we view the objects with completely synthetic lighting (or lighting setup), with little regard to how accurately the output matches the reality, but just that they show us the 3D model or point cloud.

This is where physically based rendering (PBR) comes in. In short, it is used to accurately simulate lighting in a scene according to a model of the laws of physics. While ‘offline’ 3D renderers have been able to support these sophisticated lighting and material properties, including global illumination, HDRI lighting, texture maps of reflectance, refraction and sub-surface scattering (such as with marble), we have seen that basic viewers and web-based viewers have struggled to keep up. This announcement is exciting, as not only does it highlight the current state of the art in web-based viewing via WebGL of more sophisticated 3d datasets but also its development and adoption by a major vendor. Presented at this year’s SIGGRAPH 2014, the tech represents a step in the right direction that will enable us to more widely engage with richer, more accurate visualisations of heritage sites and archaeological artefacts.


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