Impressive 3D Caveworlds

National Geographic is known for its high standards when it comes to photo reporting. And where real-world photography reaches its limits, Cinema 4D is there to help get the job done.

The National Geographic Society was founded with the aim of exploring the globe and is best known for its periodicals, which have been published continuously since 1888. The National Geographic Magazine has long since established itself as the epitome of photographic reporting for all topics related to geography. Often, complex topics cannot be illustrated well enough simply using photography, which means that informational graphics have to be added whose quality is held to the same high standards as the original photographs. A very unique case was the report about the Gebihe caves in China. One of the cave’s chambers, the Miao chamber, was scanned with a laser and Cinema 4D was used to create spectacular informational graphics for the magazine and the National Geographic website.
The Miao chamber is approximately 852 meters long and reaches heights of 190 meters, which makes it the second largest known chamber worldwide. This enormous natural phenomenon was scanned using a laser and about 15 million measuring points were generated, which were used to create a virtual cluster of points that basically reproduces the Miao chamber virtually. Using this data and the photos shot by National Geographic photographer Carsten Peter, the Berlin, Germany-based studio for professional visualization and informational graphics, ixtract, was given the job of visualizing the chamber for the National Geographic Magazine.

The first challenge that this project presented was to create a precise model of the chamber’s spatial composition using the data supplied. When asked about the challenges faced by the ixtract team during this project, Stefan Fichtel said: “We first had to deal with the gaps in the data caused by projecting rock formations, boulders and other obstacles, which prevented the chamber from being measured in its entirety. We used Cinema 4D’s XPresso feature to create a customized Displacement object, which was placed around the object like a flexible, opaque outer skin. This object was then adapted to fit the geometry, which helped solve lighting issues later in the project.

The team also had to color the cave walls. Using textures was not an option because the size required for the desired resolution would have made them too large. “This is why we simulated all textures using Cinema 4D’s own shaders. Modifying the shaders to make them look like real cave walls required a lot of creativity! More than 100 layers in different channels were mixed while making sure that the antialiasing was flicker-free, which was a challenge in and of itself,” recalls Stefan.

The project initially called for a printed informational graphic only but as it turned out, a complex animation ended up being created for the National Geographic website. This animation was designed to be a type of virtual walkthrough of the Miao chamber. At certain points, the walkthrough were to consist of photos made by Carsten Peters. “This animation had two sections in particular that posed problems”, remembers Stefan. “First, the points from which the photos had been taken had to be located. The expedition members weren’t able to tell us where these were because it was simply too dark. The second issue that we had was that we were working within a very tight deadline and we had only 2 weeks to render about 2,400 images for 90 seconds of animation!

The Motion Camera was used to create the animated camera so that the locations of the photos were combined seamlessly with the camera’s movement. Then things suddenly got interesting during rendering: In the middle of the project it was announced that the interactive version, which had a resolution for use on iPads, had to be rendered in full HD after all – and the team had no way of knowing if the rendering could be completed on time.

Stefan Fichtel about the situation: “Unfortunately we had to do without features such as Global Illumination, etc. and had to find additional ways of keeping render times as low as possible. Render time for only one version of the 90-second animation (2,400 images) was 4.5 days (60 GHz, 50 i7 cores with 140 GB RAM). In order to meet the deadline, render times had to be reduced to 12 -15 minutes per frame, without compromising on realism, which we were fortunately able to do.”
The results achieved by the team at ixtract are outstanding and a proud Stefan Fichtel states: “National Geographic works with only two external studios worldwide – and we’re one of them!

Learn from the pros

ixtract has established itself as an studio and Stefan Fichtel has built a reputation as a Cinema 4D specialist whose abilities are reflected in the work he produces. Stefan also works as a consultant and trainer, e.g., for companies who want to integrate Cinema 4D into their existing production pipelines. Stefan offers his services either on-site or at his own facilities. The clients decide what they want to learn and Stefan will also create a customized course on an individualized or group basis. Courses are offered for beginners as well as advanced users, and specialized topics such as XPresso are also covered.

The National Geographic supercave documentary:

ixtrax Website

Miao cave link:

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