Proceduralism and Automation
March 3, 2015, Game Developer Conference, San Francisco—Luiz Kruel from Certain Affinity talked about changing development pipelines to address the growing needs of al games. The games are getting more complex and visually realistic, which requires more detail in the images.
The challenge is to have a pipeline that allows materials and models to be co-developed in a single buffer pipeline. Certain Affinity has worked on titles like “Halo” and “Call of Duty”, and found that they needed to develop materials and models at the same time. The problem with co-development is that is requires new technology and new techniques to work well.
Unfortunately, their company does a lot of projects that last less than 1 year, so their other technologies are constantly changing, which is good for the developers so as not to get bored. The other side of the coin it that this short cycle time doesn’t allow the developers time to learn much about the underlying engines and to experiment to get the best effects. As a result, everything becomes custom work.
The changes they made to their pipeline are to protect the artists from burn-out while providing a workflow that allows for creativity without the labor-intensive detail work. They want to reduce wasted efforts, so the system is designed to allow the artists to fail fast and often for faster learning.
They tried to develop an artists first policy, then add automation. The intent is to develop a symbiotic relationships between the artists, their isolated tools, and the engineering and IT groups. The evolving pipeline takes an idea towards a developed concept by taking materials that then are assembled and integrated into the game engine for a specific asset type. The formerly separate textures and materials pipeline has changed to a procedural content generation system.
Traditionally, diffusion makes specular highlights more important on glossy surfaces, so a normal surface leads to layered materials and masks for textures. By using libraries, which can be existing ones, for most of the objects in scene the artist can get it right the first time. In “Enigma” they had an in-house materials pipeline and masks for various objects and all the maps are about 2k. The dDo generator tool automatically makes a set of materials and textures into a substance.
When they front-load the materials into the system, all the results look like the work of their best artist. They have a kit of assets that can be changed that is searchable through a browser for delivery to the model pipeline, reducing the time for a new asset to about 5 minutes. The models and textures start at high-resolution, then are reduced to game resolution. They bake the maps and materials into an assembly that is imported into other tools .
The high-resolution mesh is used to make a Z-Brush model that can have color and material changes. The combination of multiple meshes goes through a poly-reduce step in Houdini for voxelization. Baking the maps takes multiple steps before being moved to final substance. Compositing maps and materials sets feed a modular pipeline and the artist is able to play with the substances. The artist can also save presets for later batch flows.
Assembly of the various components requires file format conversions and the application of some fudge factors to create a DCC file with mark-ups. They can do any rigging at this point of the process. They then import the textures and materials into the engine, which allows them to view in-game approximations in a couple of hours. Now, any new 3-D concept stage content is all in the engine so the artist can just make modifications in place.
The use Forge in a game editor for Xbox games starting with a library of pieces. They use procedurals to adjust the asset models. The basic building blocks each have 32 size and shape variations. They work in Houdini on the basic block and can bevel edges, add edge loops, and add vertical and random vertices. The remaining vertices and fill are combined and they add stripes and other details. A slider allows the artist to adjust size, slew, and edges. For example, a bridge takes only 7 variations of a master asset. The master assets are modular, like a cap and middle section.
In the future, they will take more procedural prefabricated elements and simple blocks to enable automatic world building.
