For Killzone Liberation Turtle was chosen as the main rendering solution, because of its flexibility, quality and user friendly workflow, this combined with render speed made it a valuable addition to the Killzone Liberation art pipeline.

The workflow consisted of:

1. Preparing the geometry so it would be efficiently lightmapped and rendered by the game engine. (This included creating Lightmap uv-set and optimizing geometry.)
   
2. Setting up lighting for the level based on/inspired by concept paintings and gameplay requirements.
   
3. Rendering and applying the lightmaps to the geometry.
   

The creative process involved concept art made by our concept and visual design department, which Steven Tjoe (the artist responsible for lighting on Killzone Liberation) interpreted into the final results which can bee seen in the game. This all happened in passes where he started out building up the light values first and then added colour and detail (such as light profiles on lights) (see image “creative workflow” to the right). Turtle enabled him to generate very quick previews and still attain the quality needed for final output.

Turtle was used for every level in the game and for all cutscene geometry. The realtime lighting consisted of very simple lighting model (one directional light) so the environments needed to look as detailed as possible to get the maximum out of the visual style as was allowed by the memory constrains for the use of lightmaps.

Aside from the light baking, an occlusion pass was also rendered and multiplied onto the the lightmap to achieve maximum coherency and solid looking geometry (see image “technical workflow” to the right).

In addition, one of the marketing artists used an occlusion pass, a light pass render and a specular pass render to help create the marketing paint (see top right image). It was rendered at 4k pixels high without any problem.

Visual style is very important for our games, and because the Killzone style is such a specific gritty one we wanted to make sure that this also was translated well to the portable platform. Turtle helped us get there much quicker then other rendering solutions could.

Guerrilla Games is currently working on a new Killzone title for PlayStation 3. And Roderick tells us that Turtle is being used throughout the whole Killzone asset pipeline; vehicles, characters, environments, lighting, it all gets a Turtle treatment somewhere along the line. We certainly look forward to seeing the results – guess we're not the only ones.

While waiting for the game you can read more about Killzone and Guerrilla here.

Or check out some more cool images from Killzone: Liberation in the Turtle gallery.