Line and Curve Prims#

Utility functions to create geometric Line and Curve descriptions.

UsdGeomBasisCurves prims can represent multiple distinct, potentially disconnected curves. All curves within the prim must respect the same basis and wrap values. For example, one prim could contain 1 million non-periodic Bezier curves, but it cannot contain a mix of Bezier & bSpline curves, nor can it contain a mix of periodic, non-periodic, and pinned curves.

Linear curves are also represented by UsdGeomBasisCurves; in this case the type attribute is “linear” and the basis attribute can be ignored.

Normals are another a special case for UsdGeomBasisCurves; authoring normals will result in oriented ribbons rather than smooth tubes.

Functions#

pxr::UsdGeomBasisCurves usdex::core::defineCubicBasisCurves(pxr::UsdStagePtr stage, const pxr::SdfPath &path, const pxr::VtIntArray &curveVertexCounts, const pxr::VtVec3fArray &points, const pxr::TfToken &basis=pxr::UsdGeomTokens->bezier, const pxr::TfToken &wrap=pxr::UsdGeomTokens->nonperiodic, std::optional< const FloatPrimvarData > widths=std::nullopt, std::optional< const Vec3fPrimvarData > normals=std::nullopt, std::optional< const Vec3fPrimvarData > displayColor=std::nullopt, std::optional< const FloatPrimvarData > displayOpacity=std::nullopt)

Defines a batched Cubic UsdGeomBasisCurves prim on the stage.

pxr::UsdGeomBasisCurves usdex::core::defineCubicBasisCurves(pxr::UsdPrim parent, const std::string &name, const pxr::VtIntArray &curveVertexCounts, const pxr::VtVec3fArray &points, const pxr::TfToken &basis=pxr::UsdGeomTokens->bezier, const pxr::TfToken &wrap=pxr::UsdGeomTokens->nonperiodic, std::optional< const FloatPrimvarData > widths=std::nullopt, std::optional< const Vec3fPrimvarData > normals=std::nullopt, std::optional< const Vec3fPrimvarData > displayColor=std::nullopt, std::optional< const FloatPrimvarData > displayOpacity=std::nullopt)

Defines a batched Cubic UsdGeomBasisCurves prim on the stage.

pxr::UsdGeomBasisCurves usdex::core::defineLinearBasisCurves(pxr::UsdStagePtr stage, const pxr::SdfPath &path, const pxr::VtIntArray &curveVertexCounts, const pxr::VtVec3fArray &points, const pxr::TfToken &wrap=pxr::UsdGeomTokens->nonperiodic, std::optional< const FloatPrimvarData > widths=std::nullopt, std::optional< const Vec3fPrimvarData > normals=std::nullopt, std::optional< const Vec3fPrimvarData > displayColor=std::nullopt, std::optional< const FloatPrimvarData > displayOpacity=std::nullopt)

Defines a batched Linear UsdGeomBasisCurves prim on the stage.

pxr::UsdGeomBasisCurves usdex::core::defineLinearBasisCurves(pxr::UsdPrim parent, const std::string &name, const pxr::VtIntArray &curveVertexCounts, const pxr::VtVec3fArray &points, const pxr::TfToken &wrap=pxr::UsdGeomTokens->nonperiodic, std::optional< const FloatPrimvarData > widths=std::nullopt, std::optional< const Vec3fPrimvarData > normals=std::nullopt, std::optional< const Vec3fPrimvarData > displayColor=std::nullopt, std::optional< const FloatPrimvarData > displayOpacity=std::nullopt)

Defines a batched Linear UsdGeomBasisCurves prim on the stage.

Functions#

pxr::UsdGeomBasisCurves usdex::core::defineCubicBasisCurves(
pxr::UsdStagePtr stage,
const pxr::SdfPath &path,
const pxr::VtIntArray &curveVertexCounts,
const pxr::VtVec3fArray &points,
const pxr::TfToken &basis = pxr::UsdGeomTokens->bezier,
const pxr::TfToken &wrap = pxr::UsdGeomTokens->nonperiodic,
std::optional<const FloatPrimvarData> widths = std::nullopt,
std::optional<const Vec3fPrimvarData> normals = std::nullopt,
std::optional<const Vec3fPrimvarData> displayColor = std::nullopt,
std::optional<const FloatPrimvarData> displayOpacity = std::nullopt,
)#

Defines a batched Cubic UsdGeomBasisCurves prim on the stage.

Attribute values will be validated and in the case of invalid data the Curves will not be defined. An invalid UsdGeomBasisCurves object will be returned in this case.

Values will be authored for all attributes required to completely describe the Curves, even if weaker matching opinions already exist.

  • Curve Vertex Counts

  • Points

  • Type

  • Basis

  • Wrap

  • Extent

The “extent” of the Curves will be computed and authored based on the points and widths provided.

The following common primvars can optionally be authored at the same time using a PrimvarData to specify interpolation, data, and optionally indices or elementSize.

  • Widths

  • Normals

  • Display Color

  • Display Opacity

For both widths and normals, if they are provided, they are authored as primvars:widths and primvars:normals, so that indexing is possible and to ensure that the value takes precedence in cases where both the non-primvar and primvar attributes are authored.

Parameters:

  • stage – The stage on which to define the curves.

  • path – The absolute prim path at which to define the curves.

  • curveVertexCounts – The number of vertices in each independent curve. The length of this array determines the number of curves.

  • points – Vertex/CV positions for the curves described in local space.

  • basis – The basis specifies the vstep and matrix used for cubic interpolation. Accepted values for cubic curves are UsdGeomTokens->bezier, UsdGeomTokens->bspline, or UsdGeomTokens->catmullRom.

  • wrap – Determines how the start and end points of the curve behave. Accepted values are UsdGeomTokens->nonperiodic, UsdGeomTokens->periodic, and UsdGeomTokens->pinned (bspline and catmullRom only).

  • widths – Values for the width specification for the curves.

  • normals – Values for the normals primvar for the curves. If authored, the curves are considered oriented ribbons rather than tubes.

  • displayColor – Values to be authored for the display color primvar.

  • displayOpacity – Values to be authored for the display opacity primvar.

Returns:

UsdGeomBasisCurves schema wrapping the defined UsdPrim

pxr::UsdGeomBasisCurves usdex::core::defineCubicBasisCurves(
pxr::UsdPrim parent,
const std::string &name,
const pxr::VtIntArray &curveVertexCounts,
const pxr::VtVec3fArray &points,
const pxr::TfToken &basis = pxr::UsdGeomTokens->bezier,
const pxr::TfToken &wrap = pxr::UsdGeomTokens->nonperiodic,
std::optional<const FloatPrimvarData> widths = std::nullopt,
std::optional<const Vec3fPrimvarData> normals = std::nullopt,
std::optional<const Vec3fPrimvarData> displayColor = std::nullopt,
std::optional<const FloatPrimvarData> displayOpacity = std::nullopt,
)#

Defines a batched Cubic UsdGeomBasisCurves prim on the stage.

This is an overloaded member function, provided for convenience. It differs from the above function only in what arguments it accepts.

Parameters:

  • parent – Prim below which to define the curves.

  • name – Name of the curves.

  • curveVertexCounts – The number of vertices in each independent curve. The length of this array determines the number of curves.

  • points – Vertex/CV positions for the curves described in local space.

  • basis – The basis specifies the vstep and matrix used for cubic interpolation. Accepted values for cubic curves are UsdGeomTokens->bezier, UsdGeomTokens->bspline, UsdGeomTokens->catmullRom.

  • wrap – Determines how the start and end points of the curve behave. Accepted values are UsdGeomTokens->nonperiodic, UsdGeomTokens->periodic, and UsdGeomTokens->pinned (bspline and catmullRom only).

  • widths – Values for the width specification for the curves.

  • normals – Values for the normals primvar for the curves. If authored, the curves are considered oriented ribbons rather than tubes.

  • displayColor – Values to be authored for the display color primvar.

  • displayOpacity – Values to be authored for the display opacity primvar.

Returns:

UsdGeomBasisCurves schema wrapping the defined UsdPrim

pxr::UsdGeomBasisCurves usdex::core::defineLinearBasisCurves(
pxr::UsdStagePtr stage,
const pxr::SdfPath &path,
const pxr::VtIntArray &curveVertexCounts,
const pxr::VtVec3fArray &points,
const pxr::TfToken &wrap = pxr::UsdGeomTokens->nonperiodic,
std::optional<const FloatPrimvarData> widths = std::nullopt,
std::optional<const Vec3fPrimvarData> normals = std::nullopt,
std::optional<const Vec3fPrimvarData> displayColor = std::nullopt,
std::optional<const FloatPrimvarData> displayOpacity = std::nullopt,
)#

Defines a batched Linear UsdGeomBasisCurves prim on the stage.

Attribute values will be validated and in the case of invalid data the Curves will not be defined. An invalid UsdGeomBasisCurves object will be returned in this case.

Values will be authored for all attributes required to completely describe the Curves, even if weaker matching opinions already exist.

  • Curve Vertex Counts

  • Points

  • Type

  • Wrap

  • Extent

The “extent” of the Curves will be computed and authored based on the points and widths provided.

The following common primvars can optionally be authored at the same time using a PrimvarData to specify interpolation, data, and optionally indices or elementSize.

  • Widths

  • Normals

  • Display Color

  • Display Opacity

For both widths and normals, if they are provided, they are authored as primvars:widths and primvars:normals, so that indexing is possible and to ensure that the value takes precedence in cases where both the non-primvar and primvar attributes are authored.

Parameters:

  • stage – The stage on which to define the curves.

  • path – The absolute prim path at which to define the curves.

  • curveVertexCounts – The number of vertices in each independent curve. The length of this array determines the number of curves.

  • points – Vertex/CV positions for the curves described in local space.

  • wrap – Determines how the start and end points of the curve behave. Accepted values for linear curves are UsdGeomTokens->nonperiodic and UsdGeomTokens->periodic.

  • widths – Values for the width specification for the curves.

  • normals – Values for the normals primvar for the curves. If authored, the curves are considered oriented ribbons rather than tubes.

  • displayColor – Values to be authored for the display color primvar.

  • displayOpacity – Values to be authored for the display opacity primvar.

Returns:

UsdGeomBasisCurves schema wrapping the defined UsdPrim

pxr::UsdGeomBasisCurves usdex::core::defineLinearBasisCurves(
pxr::UsdPrim parent,
const std::string &name,
const pxr::VtIntArray &curveVertexCounts,
const pxr::VtVec3fArray &points,
const pxr::TfToken &wrap = pxr::UsdGeomTokens->nonperiodic,
std::optional<const FloatPrimvarData> widths = std::nullopt,
std::optional<const Vec3fPrimvarData> normals = std::nullopt,
std::optional<const Vec3fPrimvarData> displayColor = std::nullopt,
std::optional<const FloatPrimvarData> displayOpacity = std::nullopt,
)#

Defines a batched Linear UsdGeomBasisCurves prim on the stage.

This is an overloaded member function, provided for convenience. It differs from the above function only in what arguments it accepts.

Parameters:

  • parent – Prim below which to define the curves.

  • name – Name of the curves.

  • curveVertexCounts – The number of vertices in each independent curve. The length of this array determines the number of curves.

  • points – Vertex/CV positions for the curves described in local space.

  • wrap – Determines how the start and end points of the curve behave. Accepted values for linear curves are UsdGeomTokens->nonperiodic and UsdGeomTokens->periodic.

  • widths – Values for the width specification for the curves.

  • normals – Values for the normals primvar for the curves. If authored, the curves are considered oriented ribbons rather than tubes.

  • displayColor – Values to be authored for the display color primvar.

  • displayOpacity – Values to be authored for the display opacity primvar.

Returns:

UsdGeomBasisCurves schema wrapping the defined UsdPrim

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