The SPRI web application offers translation of geometric CAD data content in STEP (ISO 10303) into X3D models. This translation allows the SPRI server to present both text-based and 3d visualizations of the content of a STEP exchange file. The web standards based interface makes the X3D content, delivered in XML encoding, available as a direct file download or to a X3D viewer embedded in a web browser window. As commercial CAD applications often offer export into the STEP neutral format, this STEP to X3D translation offers a path to generate X3D content using the modelling capabilities of these applications. Furthermore, as the X3D content is delivered in XML encoding, the geometric X3D nodes are readily extracted and combined (with opportunity to modify appearance) using standard XML tools.

The SPRI server is designed to follow the principles of the REST architectural style. Every STEP file uploaded to the server is represented by a tree of resources, each resource addressed by a persistent URL. These resources are created when a STEP file is uploaded to the server through an HTML form available on the main page.

A number of STEP files have been uploaded and are available for demonstration purposes through a demo group directory. One procedure for navigating the resource tree to locate available 3d models is:

1. Browse to the main dataset resource for an uploaded file [example]
2. From dataset resource choose (click) the Assemblies resource [example]
3. From assemblies resource choose (click) available 3D models for the parts described in the originating STEP file

The main dataset resource for a file is retrieved from a directory, as above, or is returned from a successful upload of a STEP file.

Additional information: Slide show describing SPRI server

The geometric models returned by the SPRI server make extensive use of the NurbsTrimmedSurface node of the NURBS component of the X3D standard. The X3D files are declared as Interchange profile, with an additional component requirement of NURBS level 4. These models can be rendered by the Octaga Player X3D viewer, both stand-alone and as an embedded web browser object (web browser embedding is currently supported only on the Windows platform).