Capturing 3D data with Artec Eva structured light scanner at the Royal Ontario Museum.

A major initiative of the Tianlongshan Caves Project is the use of up to date technology to record 3-dimensional model data of sculptures and caves as well as and high-resolution photographic images. The data then is revealed and archived in the project website, including interactive 3D model and high-resolution image viewing. Finally, a major interactive digital exhibition will be developed.

As of May 2016 the Project team has scanned and created high-resolution 3D models from approximately 100 sculpture fragments located in over 20 museums and collections around the world. We plan to conduct scanning of the cave interiors in the summer of 2016 working with Chinese project collaborators.

The Project released the first version of the project website in May 2016. The website includes interactive high-resolution sculpture 2D image display, as well as a unique 3D model-viewing technology. The website allows searching and selection of sculptures based on a number of criteria including figure type, dynasty, museum, and original cave locations.

3D Scanning and Digital Model Creation Technology

The work of scanning and creating digital 3D models of the sculptures originally from the Tianlongshan caves took place from 2014 to 2016.

The scanning technology used is from Artec Group, including both the Artec Eva and Spider structured light scanners with the necessary Artec Studio model capture and processing software. The Artec scanners captured both the surface geometry of the sculptures as well as the surface color. The surface color is photographed using a circular flash which eliminates unwanted burnt in shadows. The Eva scanner was used for larger more complex sculptures, while the higher resolution Spider scanner was used for head sized and smaller sculptures.

The Project choice of the Artec scanners was based on a number of important unique features. These scanners are compact, portable, and hand held during the scanning process. This was especially important as we normally carried out the scanning at museums. The Artec Studio software includes all the features needed to create usable final 3D models. The resulting models are of high enough resolution for exhibition display.

Meshlab software was used for model viewing, format conversion and final model alignment. Adobe Photoshop was used for final texture color correction.

Scanning hardware and software details:
Artec Spider and Eva scanners
Artec Studio software
Sager high performance 17" laptop PCs (32G RAM, NVidia GPU)
Meshlab software
Adobe Photoshop

Website Development Technology

The Project implemented the main website structure with the Drupal content management software running on a standard LAMP web server.

The website displays high-resolution sculpture perspective photographs using Zoomify software though a sophisticated tiling system to effectively display fine details of the sculpture photos.

The Tianlongshan Caves Project website's interactive 3D model viewing uses a proprietary licensed software developed for the Xiangtangshan Caves Project. During model manipulation, the software renders a low resolution data set using the browser’s WebGL functionality. When model manipulation is not taking place, a high-resolution rendering of the model is displayed from the server side. Model manipulation functions include rotate, zoom in and out, panning, and changing the light position.

Website software details:
Drupal 7 content management software
Ubuntu Linux LAMP web server
Zoomify image viewing Javascript software library, and file preparation utility program
Proprietary 3d viewing Javascript library, and server CGI executable program

Exhibition Development Technology

The Project developed a prototype exhibition for the University of Chicago Center in Beijing in September 2015 that uses 'live' rendering of the sculpture 3D model data. The displays render 3D model animated displays in real-time, without using videos. Real-time rendering allows the addition of user interaction and control of the 3D model displays. Future Tianlongshan Cave project exhibitions will attempt a number of different user interaction strategies.

The exhibition consists of 8 HD monitors, each attached to an Apple Mac mini computer. The Cinder C++ creative coding library is used as a framework layer for effectively integrating C++, OpenGL 3D model display, 2D image display and text display. The OpenGL live rendering with the Mac mini GPU maintains frame rates of 30 fps when rendering 2 million triangle textured 3D models.

Exhibition software and hardware details:
Cinder OSX library for creative coding in C++
Apple Mac mini computers
HD digital display monitors of various sizes