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REFERENCE MANUAL

Data Fields
A3DUVParameterizationData Struct Reference

Structure for parameterizing surfaces. More...

Data Fields

A3DUns16 m_usStructSize
 
A3DDomainData m_sUVDomain
 
A3DBool m_bSwapUV
 
A3DDouble m_dUCoeffA
 
A3DDouble m_dVCoeffA
 
A3DDouble m_dUCoeffB
 
A3DDouble m_dVCoeffB
 

Detailed Description

Structure for parameterizing surfaces.

Version
2.0

This structure is used in surface definitions (see Surfaces Module). Its members specify a trimming domain (2-dimensional range) and parameterization settings.

It describes a surface reparameterization regarding the implicit parameterization that corresponds to its canonical form. Here are some important points:

Here is the evaluation formula for a given parameterization setting:

if (swap_uv)
{
   implicit_param.u = parameterization_on_u_coeff_a * param.u + parameterization_on_u_coeff_b
   implicit_param.v = parameterization_on_v_coeff_a * param.v + parameterization_on_v_coeff_b
}
else
{
   implicit_param.u = parameterization_on_v_coeff_a * param.v + parameterization_on_v_coeff_b
   implicit_param.v = parameterization_on_u_coeff_a * param.u + parameterization_on_u_coeff_b
}

To ensure that implicit_param.u(min) < implicit_param.v(min) and implicit_param.u(max) < implicit_param.v(max), you must specify parameterization values.

This example shows the settings to reparameterize a cylinder of 25mm height, having an implicit parameterization of 2 PI radian in u and height in v, to a domain of (0,0) and (1,1):

And this example shows the member settings to retain the implicit parameterization (reparameterization is unnecessary):

Field Documentation

A3DUns16 A3DUVParameterizationData::m_usStructSize

Reserved; must be initialized by A3D_INITIALIZE_DATA.

A3DDomainData A3DUVParameterizationData::m_sUVDomain

Definition domain.

A3DBool A3DUVParameterizationData::m_bSwapUV

Need to swap U and V coordinates.

A3DDouble A3DUVParameterizationData::m_dUCoeffA

Coefficient for reparameterization along u vector.

A3DDouble A3DUVParameterizationData::m_dVCoeffA

Coefficient for reparameterization along v vector.

A3DDouble A3DUVParameterizationData::m_dUCoeffB

Coefficient for reparameterization along u vector.

A3DDouble A3DUVParameterizationData::m_dVCoeffB

Coefficient for reparameterization along v vector.