# BrepData

Entity type is `kA3DTypeTopoBrepData`.

## Orientations

Here are some important points about `A3DTopoBrepData`entity orientation:

- Edges are implicitly oriented from the Start vertex toward the End vertex.
- 3D curves referenced by edges are oriented from the Start vertex toward the End vertex.
- Orientation with loop, which relates to the corresponding edge.
- Orientation UV with loop, which relates to the space parametric curve attached to the co-edge, if defined.
- Co-edge has two flags that describe orientation:
- Loop is oriented regarding Ampere rule (in surface parametric space).
- Surface is oriented with the shell so that normals point from the material to the void.

Generally, a face containing a hole is defined with two loops having the same orientation. The outside loop is defined by the `m_uiOuterLoopIndex`member of an `A3DTopoFaceData`structure, regardless of orientation. To get the real face normal vector, you must consider the surface normal vector and the `m_pucOrientationWithShell`member of the `A3DTopoShellData`structure.

sa `A3DTopoBrepData`, `A3DTopoBrepDataData`, A3DTopoBrepDataGet, A3DTopoBrepDataCreate

Returns

> `A3D_SUCCESS`on success, or an error code on failure

Structures

- `A3DTopoBrepDataData`

Functions

- `A3DTopoBrepDataGet()`
- `A3DTopoBrepDataCreate()`
- `A3DTopoBrepDataGetFaces()`
- `A3DTopoBrepDataGetEdges()`
- `A3DTopoFaceGetShellAndOrientation()`
- `A3DTopoFaceGetShell()`
- `A3DTopoLoopGetFace()`

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