CGspeak demystified

Just as the ins and outs of Photoshop’s toolset can seem very complex to an experienced 3D artist who’s only ever used Photoshop to tweak textures, so 3D jargon can seem unfathomable to the newcomer. The key to making sense of it is that almost everything in a 3D suite – apart from the basic modelling and animation tools – exists because rendering everything using physically accurate ray-tracing would take longer than finding a British tennis player who could win Wimbledon.

So most of the terminology of 3D suites refers to things that make rendering faster. That insight alone won’t make everything clear, so here we explain ten CG terms you’ve probably heard but never fully understood:

1 Ray-tracing Rendering a scene by working out how rays from light sources reach the camera, either directly or by reflection off objects

2 Ambient occlusion Taking into account indirect lighting – light bouncing off nearby non-reflective surfaces – to achieve greater realism. In practice, the technique makes points close to objects or surfaces appear darker or shadowed

3 Global illumination A more precise, and thus also slower, way of representing indirect lighting than ambient occlusion offers

4 Multi-pass rendering Running multiple renders with different settings/effects and outputting the results as individual layers for easy manipulation in software such as Photoshop or After Effects

5 Primitives Basic geometrical objects – such as a sphere, cube, torus (ring doughnut), even a teapot (a bit of a 3D in-joke) – that can be combined or edited to create more complex shapes

6 Subdivision surfaces Small polygonal elements assembled together to model complex surfaces

7 Texture map A 2D image applied to the surface of a 3D object to give it more detail

8 Reflection map A special case of texture mapping where the 2D image represents the object’s environment reflected in the object

9 UV coordinates Data defining position on the surface of a 3D object, allowing texture maps to be placed

Hi-res des res

The X3 agency created promotional images (right and bottom right) of the Bellevue Residence in Brasov, Romania, while it was still being built. The studio used 3ds Max for the interior and exterior modelling, Photoshop for matte painting and artwork creation, and After Effects for compositing animated visualisations.

“We kicked off the project with thorough research into the architectural plans and a photo shoot of the location from various perspectives and at different times of the day,” says X3 art director Sorin Bechira. “We thus managed to recreate the surrounding landscape, including the mountains and a neighboring town, just by combining and processing photos – avoiding the need for a 3D recreation of the entire landscape.

“For the vegetation, we used a combination of 3D elements and 2D sprites in order to convey a realistic image and to improve the rendering time.”

According to Bechira, the biggest challenge was the sheer level of quality they wanted to achieve within the given timeframe and budget.

“Because we are not fans of simplistic solutions, we went for a complete interior and exterior, day and night presentation of the complex,” he explains. “We had to deal with different illumination settings, according to the sun’s position. This also made the compositing more difficult as we had to even out elements for all the illumination moods we were going for – sunrise, midday, sunset and night.”