Standards

Standards are at the core of interoperability and reusability.

Presagis supports industry standards that make the development of both M&S and embedded applications easier and more efficient. Their entire product portfolio is built on open standards, so Presagis products can fit into most development pipelines. In addition, any Presagis software application can leverage user plugins and can integrate with other third party products.

Modeling & Simulation

• ARINC 661
• DO-178B

TerraPage

While many model exchange standards exist, none are well suited for the use of large scale terrain databases. Many of the visual systems available on the market today, including flight simulators and ground-based trainers, now support large applications that require large area terrain databases. However, while these formats exist for more expensive systems, they have not become standards either because of usability (many are in-house contractor systems) or because they are part of a proprietary product. In fact, the lack of a terrain database paging standard was holding the industry back, particularly in the area of PCs.

The Standard

TerraPage was developed in 1998 to address this key market requirement for an open standard for terrain database paging. TerraPage is a Presagis-developed and supported on-disk format designed for large area terrain and texture paging. In addition to providing quick and easy access to extremely large spatial terrain databases, this standard also fulfills the role of an optimized disk format for visual systems that may not already have one. Consequently, it provides both well defined spatial organization for terrain paging and pre-optimized data structures, such as triangle strips and fans, for use on the current generations of graphics hardware.

TerraPage is not itself a runtime system and neither is it a scene graph of its own. Instead, it is built to interface with the scene graph from an existing runtime system. The TerraPage format is produced by a terrain database tool, such as Terra Vista, and is used by a runtime system to visualize the terrain.

TerraPage has a number of advantages:

• Paging - Terrain tiles can be paged from disk individually as needed. Different terrain LODs are stored separately.
• Texture/Model Indexing - All the texture & model references go at the beginning of an archive. This tells the user what he/she will encounter on reading an archive.
• Per-tile texture/model lists - Each tile gives the user a concise list of the textures and models it uses. This enables run-time systems, for example, to page in textures as they're needed.
• Optimized geometry - The basic geometry structure supports triangle strips and fans. In addition, the material indexing provides for up-front texture and material allocation, if desired.

Presagis TerraPage Support

Presagis continues to develop and support TerraPage through its continued support of the Terra Vista product family. Terra Vista outputs the TerraPage format to be used in a runtime system to visualize the terrain.