Combined method of 3D model of archaeological objects optimization for a mobile app

Digitalization of an archaeological object aims to accurately represent its topology and texture. Photogrammetric digitalization of small models with a volume up to 20 cm3 is only of acceptable quality if the number of polys is 300k or more and resolution of diffuse textures is more than 8k. Objects having such characteristics occupy minimum 30Mb of disc space and have some restrictions on use. In fact, such models can be used for static but not real-time visualization in mobile app since they require much computational resources. That is why we examined methods of both automatic and manual optimization and then came up with a combined method. Initially hipoly models exported from Agisoft Photoscan (file format is *.fbx, 8 bit *.png texture) were automatically optimized with MeshLab through a quadric edge collapse decimation algorithm that reduced the number of polys by 80-95% so we got draft lowpoly models. They were processed with 3Ds Max to refine topology on basis of hipoly versions of models with graphite modeling tools. Then albedo, normal and ambient occlusion maps were baked in HandPlaneBaker in order to add the topology features lost while optimization. The textures were then combined in Quixel Suite and the process of optimization had been completed. As a result, we got the realistic models with approximately 4.5k polys and 2k texture resolution.

Keywords: digitization, 3D model, archaeology, optimization of 3D models, virtual archaeology, visualization, mobile app, video game, game development.

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