Following the brave rescue of a football team in the Tham Luang Cave System, the mapping of the entire system became an important task

As a result of our numerous cave scanning assignments using the RIEGL VZ-400, Commendium were contacted by MSP TV to assist them with an episode of the ‘Drain the Oceans’, a series on behalf of Nat Geo TV. Having worked for The National Geographic on several occasions, it was great to be back working on Drain the Oceans: Thai Cave Rescue.  

Our brief was to 3D survey a 6km stretch of the Tham Luang Cave in Thailand, using LiDAR terrestrial scanners. The data from the scans would be processed to make a photorealistic CGI 3D model of the cave journey. The 3D model itself illustrates part of the Thailand Cave Rescue story deep in the Chiang Rai province. The cave system proved to be every bit as challenging as we had imagined. In the dry sections, the cave was very easy to navigate for experienced cavers. However, then came the slippery section with lots of clambering over large boulders. With each of us carrying about 20kg, the humidity was draining for the crew.

Scanning in caves requires additional care as there aren’t the usual aids such as GNSS to help with automatic registration, although the almost 500 scanning stations stitched well with the assistance of MSA tools in the RiSCAN PRO software. Once back in the UK the real work began. The photos were processed to colour-match and check level brightness. The scans were re-stitched and cleaned up to eliminate noise and unnecessary items, such as people/crew. The scans were also adjusted with GPS co-ordinates, to ensure the cave would be orientated correctly when we merged both the surface scans and underground models.

The next phase was working with the VFX (visual effects) team. Over several weeks we created several models to create CGI imagery for the film. We built an animated diver, constructed sections of the cave in meticulous detail, tested various animations and effects. The final result is superb and is available on the Disney Channel, Disney/Nat Geo/Drain the Oceans/Series 2.

Taking the VZ-400 through the cave
Taking the VZ-400 through the cave

Credit: Mark Burkey

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A break for filming
A break for filming

Credit: Mark Burkey

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The entire Tham Luang cave system
The entire Tham Luang cave system

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Taking the VZ-400 through the cave
Taking the VZ-400 through the cave

Credit: Mark Burkey

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A video of the final CGI product, generated using LiDAR scans and featured on the Drain The Ocean show can be found here.

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