Visual art assets that are generated from the various Digital Content Creation (DCC) tools are exported into intermediate file formats. This can happen through linked nodes, with specific names, or with additional information attached to the object. Most times, the assets become some sort of an input for the entities in Sandbox, which use the embedded information to execute scripts in a useful way.
Over time, Crytek will switch all 3D content and 3D animations to the Collada file format as the intermediate asset file format. Currently, Autodesk Motionbuilder uses Collada as its export format. 2D textures are stored in a special Crytek version of the uncompressed TIFF format. These intermediate files are converted by the Using the Resource Compiler (RC) into the final target file format.
The following diagram represents the Art Asset Pipeline as the assets are created in content creation programs, exported with various exporters and plugins, and converted by the Resource Compiler into formats accepted by the Sandbox Editor. See also: Art Pipeline Roadmap.
Information To Be Setup In The DCC Tool
- Asset structure.
- 3D rendering mesh.
- Pivot position.
- Scaling information.
- Vertex colors.
- Material setup.
- Hierarchical structures.
- Helper nodes.
- Level Of Detail (LOD).
- Occlusion properties.
- Collision properties.
- Physics settings.
- Breakability setup.
- Bending properties for the vegetation.
- Weighting to skeletons.
All the information, except the material setup, is done exclusively in the DCC tool. For the material setup, associate polygons only with material names, not with specific values within a DCC tool. The final setup is done in the Sandbox Material Editor.
3D level elements are created within the supported DCC tool. The setup contains smoothing groups (hard edges), vertex colors, UV coordinates, associating polygons with materials and physics information, LODs, occlusion planes, skeletal weighting, skeleton information, mass/density, and breakability data. There are three engine file formats that store CRYENGINE compatible object data. .cgf, .cga, and .chr. More information about the file formats can be found in the Art Asset File Types reference document.
Materials are generally set up in the Sandbox Material Editor. Within the DCC tool, you can set up textures and diffuse colors, which are also transferred when a material is created within the DCC tool. Settings still need to be tweaked within the Sandbox Editor (shader model, material effect, specular settings). The Sandbox material data is stored in an XML file with the extension, .mtl. CRYENGINE automatically looks for an .mtl file that corresponds with the material name of an object that was applied to it within the DCC tool.
CRYENGINE can handle the .tif and .dds texture formats for the in game asset materials. You can either choose to directly assign a .dds file or use a special version of the TIFF format that is written with the CryTIF plugin. The Resource Compiler uses the metadata in the .tif file to convert the texture into the correct target format. This is especially useful if you need to output to several platforms, with different target file formats.
Skeletons, hierarchies are animated in the DCC tool and written to intermediate files. They are compressed and optimized before they go into the engine. There are two existing file formats for animations: .anm and .i_caf/.caf. ANM is for hierarchical animations like on vehicles, and I_CAF/CAF is for skeleton animations, with a weighted polygonal skin.