OpenCASCADE: Standard geometric topology model

OpenCASCADE: Standard geometric topology model

OpenCASCADE is an open source 3D geometric modeling software library, the most important module of which is the model algorithm module. The model algorithm module is the core component of OpenCASCADE, which provides basic three-dimensional geometric objects, geometric operations and topological relations, and is convenient for three-dimensional geometric modeling.

In OpenCASCADE, standard geometric topology objects are widely used as the most basic elements. Standard geometric topology objects are points, lines, surfaces, and solids. These basic elements can be combined to form more complex geometry. OpenCASCADE provides several types of standard geometric topology objects, such as points (TopoDS_Vertex), edges (TopoDS_Edge), faces (TopoDS_Face) and solids (TopoDS_Solid).

In addition to basic geometric objects, OpenCASCADE also provides some commonly used geometric operations, such as point projection, intersection points between curves, section lines on surfaces, and deformation of solids. These geometric operations are directly available for operations between standard geometric topology objects.

Here is a simple example showing how to create a triangular face:

#include <BRepBuilderAPI.hxx>
#include <TopoDS.hxx>
#include <TopoDS_Face.hxx>
#include <gp_Pnt.hxx>

int main()
{
    // 创建三个点
    gp_Pnt p1(0, 0, 0);
    gp_Pnt p2(0, 10, 0);
    gp_Pnt p3(10, 0, 0);

    // 使用BRepBuilderAPI创建三角形面
    BRepBuilderAPI_MakeFace faceMaker(p1, p2, p3);
    TopoDS_Face face = faceMaker.Face();

    return 0;
}

Through the BRepBuilderAPI_MakeFace class, we can easily create a triangular face composed of three points. In this example, we define three points p1, p2 and p3, and pass them to the constructor of the BRepBuilderAPI_MakeFace class. Then, we can use the Face() method to get the created face object.

OpenCASCADE provides a rich library of functions that can help us complete geometric modeling tasks conveniently. If you are interested in geometric modeling, you may wish to take some time to understand the various functions of OpenCASCADE, I believe it will be helpful to you.