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STEPcode (formerly NIST's STEP Class Library) is used with IFC, STEP, and other standards that utilize the technologies of ISO10303 (STEP). It generates C++ and Python from EXPRESS (10303-11) schemas. The code is capable of reading and writing STEP Part 21 exchange files. It also utilizes Parts 22 and 23 (SDAI and its C++ binding).
C C++ Python CMake Bison
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cmake rework version_string logic - only write the file if the git commit (…
data update AP209 ATS files. enum element_order now has the _order prefix …
doc More whitespace and case tweaks
example/ap203min Add ExternalProject_add based build of ap203min example
include Patch for MSVC2013 compilation
misc Rename fedex_python and fedex_plus to exp2python and exp2cxx respecti…
src 1. Heap corruption error fixed at sectionReader
test add test and files for a p21read segfault.
.gitignore update .gitignore
.travis.yml tweak travis-ci more
AUTHORS bump version (0.8), update AUTHORS, NEWS for v0.8, add travis-ci buil…
CMakeLists.txt Suppress CMake warning 26 - need to figure out the 'right' approach e…
COPYING Update text files for v0.6
CTestConfig.cmake Add CMake footer comment to CMake files
ChangeLog v0.7: Update changelog, INSTALL, NEWS, README, version string
INSTALL v0.7: Update changelog, INSTALL, NEWS, README, version string
NEWS NEWS: forgot to include BRL-CAD changes rename altered rendering of sample code block
SC_VERSION.txt bump version (0.8), update AUTHORS, NEWS for v0.8, add travis-ci buil…
appveyor.yml appveyor: run fewer tests
ctest_matrix.cmake Case and whitespace on toplevel CMake files
lcov.cmake Case and whitespace on toplevel CMake files
run_ctest.cmake Case and whitespace on toplevel CMake files

Travis-CI build status: Build Status

STEPcode v0.8 --,

  • What is STEPcode? SC reads ISO10303-11 EXPRESS schemas and generates C++ source code that can read and write Part 21 files conforming to that schema. In addition to C++, SC includes experimental support for Python.

  • Renamed in April/May 2012: SC was formerly known as STEP Class Libraries, SCL for short. It was renamed because the name wasn't accurate: the class libraries make up only a part of the code.

  • Much of the work to update SC has been done by the developers of BRL-CAD, and SC (then STEP Class Library) was originally created at NIST in the 90's.

  • For information on changes version-by-version, see the NEWS file

  • Building and testing SCL - see the INSTALL file

  • For more details on the libraries and executables, see the wiki:

  • For license details, see the COPYING file. Summary: 3-clause BSD.


SC's source has been reformatted with astyle. When making changes, try to match the current formatting. The main points are:

  • compact (java-style) brackets:
    if( a == 3 ) {
        c = 5;
        function( a, b );
    } else {
        somefunc( );
  • indents are 4 spaces
  • no tab characters
  • line endings are LF (linux), not CRLF (windows)
  • brackets around single-line conditionals
  • spaces inside parentheses and around operators
  • return type on the same line as the function name, unless that's too long
  • doxygen-style comments (see

If in doubt about a large patch, run astyle with the config file misc/astyle.cfg. Download astyle from

For more info, see the wiki.

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