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Analysis Situs is the open-source application and SDK for CAD feature recognition and more.

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Why Analysis Situs?

Analysis Situs is an open-source prototyping workbench and an SDK to develop CAD/CAM/CAE algorithms. Its main driving idea is to give CAD software developers a highly intuitive, visual, and customizable incubator where new CAD algorithms get born. The workbench utilizes C++ and Tcl as the main programming languages. The application comprises a hierarchically organized data model, VTK-based 3D viewers, and a scripting console. Provided is a bunch of geometry processing algorithms, ranging from CAD feature recognition to computations on meshes.

Technology-wise, Analysis Situs builds upon OpenCascade and another in-house open-source NURBS library. It accumulates a wide range of functionalities, covering classical B-rep modeling/inspection algorithms and some state-of-the-art approaches. The latter includes some algorithms developed in the frames of scientific research of its authors. The available tools are designed to be used as a basis for derived algorithms.

The initial intention behind this software was to bridge a gap between academic researchers and industrial consumers (to solve the "technology transfer" problem). The authors also use Analysis Situs to teach students and CAD practitioners low-level geometric modeling as well as to conduct their own research.

We believe that CAD community lacks open-source software which could bridge the gap between academic researchers and industry. Also, such software should contribute to practicing "open science" in the field of industrial geometric modeling.

"Free access to code is necessary for meeting the gold standard of scientific reporting: A study's tools and methods must be described clearly enough for its results to be replicated. Only the original code provides enough detail for replication. Pseudocode of an algorithm is insufficient. Software that does not meet the minimal standard of freely available code should not be considered a scholarly contribution." [Hafer and Kirkpatrick, 2009]

As mentioned in the cited article, posting unmaintained, undocumented and not well-engineered code is not a scholarly contribution. The purpose of this web-site is to provide all necessary interfaces to Analysis Situs as a reliable, documented and maintained software. This web-site is largely a user's guide for the software and an algorithmic guide for its backbone CAD kernel.

Cite us

The following paper (full text available) puts the software into a more scientific context:

Slyadnev, S., Malyshev, A., and Turlapov, V. 2017. CAD model inspection utility and prototyping framework based on OpenCascade. GraphiCon 2017, 323-327.

BibTeX entry:

  title={{CAD model inspection utility and prototyping framework based on OpenCascade}},
  author={Slyadnev, Sergey and Malyshev, Alexander and Turlapov, Vadim},
  booktitle={GraphiCon'17 proceedings},