Data Structures | |
struct | A3DCrvCircleData |
Circle arc structure. More... | |
Functions | |
A3DStatus | A3DCrvCircleCreate (const A3DCrvCircleData *pData, A3DCrvCircle **ppCrv) |
Creates an A3DCrvCircle from A3DCrvCircleData structure. More... | |
A3DStatus | A3DCrvCircleGet (const A3DCrvCircle *pCrv, A3DCrvCircleData *pData) |
Populates the A3DCrvCircleData structure. More... | |
Detailed Description
- Version
- 2.0
Entity type is kA3DTypeCrvCircle.
The canonical form is defined with an A3DMiscCartesianTransformationData, its origin being the center of the circle and its vector X being the axis corresponding to zero parameter. The implicit parameterization is an angle expressed as radians in the range [0, 2PI].
A3DParameterizationData lets you specify reparameterization and trim.
Here are parameterization examples:
-
To specify the interval in radians, set
m_dCoeffA
to 1.0 andm_dCoeffB
to 0.0. These parameter values specify an identity conversion. -
To specify the interval in degrees, set
m_dCoeffA
to PI/180 andm_dCoeffB
to 0.0.m_dCoeffA
is the ratio of radians to degrees.
- Example of a circular arc

In the above example, the circular arc is in the XY plane (and therefore has an identity transformation), has radius R, and is restricted to the [ t0 , t1 ] interval.
If m_dCoeffA
is 1.0 and m_dCoeffB
is 0.0 and if the interval is defined as t0=0
and t1=PI/2
, then t0
corresponds to the Cartesian coordinates (R,0,0) and t1
to (0,R,0). These values for the m_dCoeffA
and m_dCoeffB
co-efficients indicate parameterization is in radians and starts at the X axis.
- Note
- Radius must be greater than 0.
- Warning
- Radius as a parameter can be modified by A3DMiscCartesianTransformationData when the transformation defines uniform scaling.
Function Documentation
A3DStatus A3DCrvCircleCreate | ( | const A3DCrvCircleData * | pData, |
A3DCrvCircle ** | ppCrv | ||
) |
Creates an A3DCrvCircle from A3DCrvCircleData structure.
- Version
- 2.0
A3DStatus A3DCrvCircleGet | ( | const A3DCrvCircle * | pCrv, |
A3DCrvCircleData * | pData | ||
) |