Survex 3d Format Specification

If you're writing in C or C++ it's strongly recommended that you use the img routine provided with Survex to read and write 3d files. Doing so means that you can take advantage of any revisions to the 3d format by simply rebuilding your software with the updated img routines, rather than having to update your own code. It also allows you to read a sub-set of the data in the file, restricted by Survey prefix.

This document only describes the more recent revisions of the 3d format (versions 3 to 7, inclusive). Version 3 was produced by Survex versions 0.97 and later, version 4 by Survex 1.1.0-1.1.3, version 5 by 1.1.4-1.1.10, version 6 by 1.1.11-1.1.14, and version 7 by versions from 1.1.15.

If you try to use this specification and find details which aren't spelled out clearly enough (or at all!) or any errors, please let us know. At least two people have successfully written code to read 3d files using this document, but that doesn't mean it can't be improved.

File Header

This consists of: