McCad - BRep to CSG

McCad是一個開源工具，能自動將BRep模型轉換成CSG模型。隨著核動力技術的發展，不斷開展新型反應堆的研究，反應堆的燃料形式和堆芯布置都較為復雜，由于蒙特卡羅(MC)方法具有強大的幾何處理能力和較高的計算精確度，它是模擬分析這些復雜堆芯的有效手段。通過使用McCad將復雜BRep模型轉換成CSG模型，CSG表示的模型可作為核反應堆芯計算蒙特卡羅(MC)方法的輸入。

McCad基于OpenCASCADE內核已經持續開發了20年，基于LGPL協議開源，感興趣的小伙伴可以下載嘗試一下：

https://github.com/inr-kit/McCAD-Library

BRep轉CSG個人感覺沒有完美的解決方案，但是應用范圍很廣。如果轉換效果好，其實還有一個用途，就是將BRep轉換的CSG模型導入到PDMS中，從而解決通過機械設備接口MEI導入STEP/IGES后PDMS模型數據變大的問題。

McCad is an open source tool for automatic conversion of B-Rep models into CSG.

McCad has been continuously developed for more than two decades. It provides automatic conversion of Boundary Representation (BREP) CAD models into Constructive Solid Geometry (CSG), the latter of which is an input syntax often used in Monte Carlo (MC) radiation transport codes. The conversion process, from BREP to CSG, is essential for high-fidelity nuclear analysis of complex nuclear facilities. McCad can convert CAD files in STEP format to different input syntaxes used with MC codes such as MCNP, TRIPOLI, Geant4, etc., so that the manual efforts on building a complex simulation model can be avoided. McCad provides an advanced algorithm to decompose complex solids into its constituent convex primitives, and generates the void space description between the solids, which is required by MC codes.

It relies on OpenCASCADE CAD kernel to perform CAD manipulations and Boolean operations. McCad has been integrated into the SALOME platform, with a detailed manual provided. It is an open-source code released under LGPL license. This code has been currently used for nuclear research institutes crossing continents, for nuclear analyses on fission reactors, fusion facilities and neutron source facilities.