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