OpenCASCADE由七个模块组成，分别如下：
| Foundation Classes基础类 | Modeling Data 建模数据 | Modeling Algorithms 建模算法 | Visualization 可视化 | Data Exchange 数据交换 | Application Framework 程序框架 |
| Kernel Classes 核心类 | 2D Geometry 二维几何体 | Primitives 基本实体 | 2D和3D通用功能 | IGES STEP | Data Framework |
| Math Utilities 数学工具 | 3D Geometry 三维几何体 | Boolean Operations 布尔操作 | 2D Visualization 2D 可视化 | AP203 AP214 | Data Storage |
| Geometry Utilities 几何工具 | Fillets and Chamfers 倒圆和倒角 | 3D Visualization 3D 可视化 | Extended data Exchange (XDE) | Application Desktop | |
| Topology 拓朴结构 | Offsets, Drafts, Sewing, Sweeps, | ||||
| Hidden Line Removal 消隐 | |||||
| Geometric Tools 几何工具 | |||||
| Topological Tools 拓朴工具 |
Module FoundationClasses; 基础类；
Toolkit TKMath
Toolkit TKernel
Module ModelingData; 造型数据；
Toolkit TKBRep
Toolkit TKG2d
Toolkit TKG3d
Toolkit TKGeomBase
Module ModelingAlgorihtms; 造型算法；
Toolkit TKBO
Toolkit TKBool
Toolkit TKFeat
Toolkit TKFillet
Toolkit TKGeomAlgo
Toolkit TKHLR
Toolkit TKMesh
Toolkit TKOffset
Toolkit TKPrim
Toolkit TKShHealing
Toolkit TKTopAlgo
Toolkit TKXMesh
Module Visualization; 可视化；
Toolkit TKD3DHost
Toolkit TKIVtk
Toolkit TKMeshVS
Toolkit TKOpenGl
Toolkit TKOpenGles
Toolkit TKService
Toolkit TKV3d
Module ApplicationFramework; 程序框架；
Toolkit TKBin
Toolkit TKBinL
Toolkit TKBinTObj
Toolkit TKCAF
Toolkit TKCDF
Toolkit TKLCAF
Toolkit TKStd
Toolkit TKStdL
Toolkit TKTObj
Toolkit TKVCAF
Toolkit TKXml
Toolkit TKXmlL
Toolkit TKXmlTObj
Module DataExchange; 数据交换；
Toolkit TKBinXCAF
Toolkit TKExpress
Toolkit TKIGES
Toolkit TKRWMesh
Toolkit TKSTEP
Toolkit TKSTEP209
Toolkit TKSTEPAttr
Toolkit TKSTEPBase
Toolkit TKSTL
Toolkit TKVRML
Toolkit TKXCAF
Toolkit TKXDE
Toolkit TKXDECascade
Toolkit TKXDEIGES
Toolkit TKXDESTEP
Toolkit TKXSBase
Toolkit TKXmlXCAF
Module Draw;
Toolkit TKD3DHostTest
Toolkit TKDCAF
Toolkit TKDraw
Toolkit TKIVtkDraw
Toolkit TKOpenGlTest
Toolkit TKOpenGlesTest
Toolkit TKQADraw
Toolkit TKTObjDRAW
Toolkit TKTopTest
Toolkit TKViewerTest
Toolkit TKXDEDRAW
Toolkit TKXSDRAW
其中基础类模块有三个工具箱：
Toolkit TKMath; 数学工具箱；
Package BSplCLib
Package BSplSLib
Package BVH
Package Bnd
Package CSLib
Package Convert
Package ElCLib
Package ElSLib
Package Expr
Package ExprIntrp
Package GeomAbs
Package PLib
Package Poly
Package Precision
Package TColgp
Package TopLoc
Package gp
Package math
Toolkit TKernel; 核心工具箱；
Package FSD
Package Message
Package NCollection
Package OSD
Package Plugin
Package Quantity
Package Resource
Package Standard
Package StdFail
Package Storage
Package TColStd
Package TCollection
Package TShort
Package Units
Package UnitsAPI
Package UnitsMethods
图：Open CASCADE Technology
图：Module FoundationClasses
图：Module ModelingData
图：Module ModelingAlgorithms
图：Module Visualization
图：Module ApplicationFramework
图：Module DataExchange
图：Module Draw
