OpenCascade BRep Format Description (2)

OpenCascade BRep Format Description

eryar@163.com

摘要Abstract：本文结合OpenCascade的BRep格式描述文档和源程序，对BRep格式进行分析，详细说明BRep的数据组织形式。结合源程序，可以对OpenCascade中Modeling Data模块中的模型数据结构进行理解。 

关键字Key Words：OpenCascade, BRep Format, ModelingData 

  

一、实例分析

OpenCascade的data目录中的face1.brep文件：

  1 DBRep_DrawableShape

  2 

  3 CASCADE Topology V1, (c) Matra-Datavision

  4 Locations 5

  5 1

  6               1               0               0            -0.4 

  7               0               1               0               0 

  8               0               0               1               0 

  9 1

 10               1               0               0            -0.4 

 11               0               1               0               0 

 12               0               0               1               0 

 13 1

 14               1               0               0             0.8 

 15               0               1               0               0 

 16               0               0               1               0 

 17 1

 18               1               0               0             0.8 

 19               0               1               0               0 

 20               0               0               1               0 

 21 2  1 1 2 1 3 1 4 1 0

 22 Curve2ds 8

 23 1 0 0.8 1 0 

 24 2 0 0 1 0 0 1 0.8

 25 1 1.82347658193698 0 0 1 

 26 1 1 -1.77459666924148 1 0 

 27 1 4.45970872524261 0 0 1 

 28 1 1 -0.225403330758516 1 0 

 29 1 0 0 1 0 

 30 2 0 0 1 0 0 1 0.8

 31 Curves 4

 32 2 0 0 0.8 0 0 1 1 0 0 0 1 0 0.8

 33 1 -0.2 0.774596669241484 0 0 0 1 

 34 1 -0.2 -0.774596669241484 0 0 0 1 

 35 2 0 0 0 0 0 1 1 0 0 0 1 0 0.8

 36 Polygon3D 0

 37 PolygonOnTriangulations 0

 38 Surfaces 4

 39 2 0 0 0 0 0 1 1 0 0 0 1 0 0.8

 40 1 0 0 0.8 0 0 1 1 0 0 0 1 0 

 41 1 -1 -1 -1 1 0 0 0 0 1 0 -1 0 

 42 1 0 0 0 0 0 1 1 0 0 0 1 0 

 43 Triangulations 0

 44 

 45 TShapes 10

 46 Ve

 47 2.0000002e-007

 48 -0.2 0.774596669241483 0.8

 49 0 0

 50 

 51 0101101

 52 *

 53 Ve

 54 2.0000002e-007

 55 -0.2 -0.774596669241484 0.8

 56 0 0

 57 

 58 0101101

 59 *

 60 Ed

 61  1e-007 1 1 0

 62 1  1 0 1.82347658193698 4.45970872524261

 63 2  1 1 0 1.82347658193698 4.45970872524261

 64 2  2 2 0 1.82347658193698 4.45970872524261

 65 0

 66 

 67 0101000

 68 +10 0 -9 0 *

 69 Ve

 70 2.0000002e-007

 71 -0.2 0.774596669241483 0

 72 0 0

 73 

 74 0101101

 75 *

 76 Ed

 77  1e-008 1 1 0

 78 1  2 0 0 0.8

 79 2  3 1 0 0 0.8

 80 2  4 3 5 0 0.8

 81 0

 82 

 83 0101000

 84 +7 0 -10 0 *

 85 Ve

 86 2.0000002e-007

 87 -0.2 -0.774596669241484 0

 88 0 0

 89 

 90 0101101

 91 *

 92 Ed

 93  1e-008 1 1 0

 94 1  3 0 0 0.8

 95 2  5 1 0 0 0.8

 96 2  6 3 5 0 0.8

 97 0

 98 

 99 0101000

100 +5 0 -9 0 *

101 Ed

102  1e-007 1 1 0

103 1  4 0 1.82347658193698 4.45970872524261

104 2  7 1 0 1.82347658193698 4.45970872524261

105 2  8 4 0 1.82347658193698 4.45970872524261

106 0

107 

108 0101000

109 +7 0 -5 0 *

110 Wi

111 

112 0101100

113 -8 0 -6 0 +4 0 +3 0 *

114 Fa

115 0  1e-007 1 0

116 

117 0101000

118 +2 0 *

119 

120 +1 0 

121 0

122 

 

显示结果如下图所示： 

Figure 1. Wireframe mode 

Figure 2. Shaded mode 

二、结论

因为OpenCascade的Brep格式是自己的格式，只用到了ModelingData模块，不使用DataExchange模块，可以作为数据交换的一种格式。 

三、参考资料

1. BNF范式：http://hi.baidu.com/xuyingming2012/item/9060029141427bd81b49df9e

2. BRep Format Description 

3. OpenCascade source code 

 

PDF Version: BRep Format Description

 

PDF Version: BRep Format Description White Paper