# A3DTopoContextData

struct `A3DTopoContextData`

  Structure for parsing or creating an `A3DTopoContext`entity.

  > 2.0

  The `m_ucBehaviour`member is an array of bits that uses values from the topology context bitmask definitions (Topology Context Data).

  > `m_dScale`is a conversion factor from the unit of the part (which is not mandatory millimeters) to the “unit” of the modeling kernel. In fact, there is NO notion of physical unit at the level of the “TopoContext”. The numbers that are stored there do not have a physical significance by themselves. To interpret them, you should take into account the unit of the part and the “TopoContext” context scale. Then, there can be further scale on the product hierarchy that should be taken into account when converting entities while respecting a given accuracy towards original geometry.

  > `A3DTopoContextData`, `A3DTopoContextGet()`, `A3DTopoContextCreate()`

  ## Index

  Variables

  - `m_ucBehaviour`
  - `m_dGranularity`
  - `m_dTolerance`
  - `m_bHaveSmallestFaceThickness`
  - `m_dSmallestThickness`
  - `m_bHaveScale`
  - `m_dScale`

Variables

A3DUns8 `A3DTopoContextData.``m_ucBehaviour`
  `A3DUns8`

  Array of bits.

A3DDouble `A3DTopoContextData.``m_dGranularity`
  `A3DDouble`

  Minimal size of an edge.

  This value is non-dimensional.

A3DDouble `A3DTopoContextData.``m_dTolerance`
  `A3DDouble`

  Global base tolerance used in the context for topological elements.

  This value is non-dimensional.

A3DBool `A3DTopoContextData.``m_bHaveSmallestFaceThickness`
  `A3DBool`

  True if next member is valid.

A3DDouble `A3DTopoContextData.``m_dSmallestThickness`
  `A3DDouble`

  Smallest thickness for a face.

  Used in internal loop processing. Default should be 100 * `m_dGranularity`.

A3DBool `A3DTopoContextData.``m_bHaveScale`
  `A3DBool`

  True if next member is valid.

A3DDouble `A3DTopoContextData.``m_dScale`
  `A3DDouble`

  Optional scale to interpret the data of the context.

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