General Model Information


This section includes various standards, conventions, and guidelines used in model creation as it relates to Halo Level Design. This section also includes editing information such as polygon counts, guidelines, and methods for trouble shooting and optimizing models.




Style Guidelines


See the Style Guidelines section under the General Level Design Information section.




Polygon Count Guidelines for Construction



The following lists the suggested maximum amount of polygons that should be used to construct a typical model of the type listed.

While the Blitzkrieg exporter and data tag compiler Tool can handle much higher polygon counts (since the same tools are used to export level geometry and other higher polygon count models such as character and vehicles), its recommended to keep the values within the range suggested for the listed model type.

Typical objects used for scenery objects include trees, rocks, bushes, and other small details.  The value listed below represents the average maximum value for scenery objects used in multiplayer levels.

NOTE: The values listed are for the Super High Model LOD (Level of Detail)



Multiplayer Scenery Objects (Models):

500 polygons




Triangle Counts  (in game)



The following lists the suggested maximum amount of triangles that should draw for the listed model.

NOTE: The values listed are for the Super High Model LOD (Level of Detail)



Multiplayer Scenery Object:

1,000 triangles



The values listed are a general guideline due to the fact that performance is affected by many factors other then triangle counts such as the number and type of materials (shaders) associated with the model.

As can be expected, the fewer triangles being drawn the better.  When creating a model, always take into account its effect on the level and the scene in which it is being placed.

When creating a new model, its always a good idea to view a similar model object that exists in the original game and see what kind of triangle counts exist for that particular model.  If creating a new tree model, check the current tree models in the game and see what are their associated triangle counts.





Overall Performance Guidelines and Suggestions



Many of the factors mentioned in the Overall Performance Guidelines and Suggestions in General Level Design Information apply to the performance of a model object in Halo.  A model objects effect on performance includes many factors, not just the pure number of triangles being drawn.

Below is a simple list of things to keep in mind when creating models for Halo:

1) Be careful of the polygon and resulting triangle counts for the model.  The model should not be created without regard for its use and placement in its intended environment.  If a level or game environment already has high triangle counts and a model is being placed in the area, the model being created should have a low triangle count and\or the environment it is being used in should have its triangle count lowered.

2) Scenery objects are used for many reasons such as decreasing the development or creation time of a level by allowing the population of common objects quickly.  The use of scenery objects also reduces memory by using multiple instances of the same model that uses the same material or shader.  Memory used by the game is also saved since the objects are not made part of the core level geometry and do not require a light map.

3) Always consider using or creating several Levels of Detail (LOD) for the model you are creating,  especially if its a very high polygon model that is used frequently in the environment and has many instances per scene.  LOD models are manually created lower polygon versions of the higher polygon model seen by the player up close.  These LODs are set to replace the higher polygon version at farther distances from the player view.  As the distance from the player view increases, lower and lower polygon versions of the model are used.  These distances can be manually set in the model tag.

4) The number of different materials or shader types per model can greatly affect performance. Try to limit the unique number of materials per model to decrease the number of materials per scene.

5) Avoid using or creating a lot of model shaders that have a lot of effects or settings or that require multiple rendering passes, this can greatly decrease performance.  Shaders with a base map, multipurpose map, detail map, detail mask, bump map, scrolling texture settings, and reflection cube map all set decreases rendering performance and uses up more memory.  Be careful when using the 2-sided model shader flag, this will double the triangle count for the faces on which it is applied.  This flag is most commonly used on the leaves for trees and foliage.

6) Watch the amount of overdraw created by having successive layers of transparent or partially transparent geometry.