usdrt::UsdGeomCamera

Defined in usdrt/scenegraph/usd/usdGeom/camera.h

Functions

Variables

class UsdGeomCamera : public usdrt::UsdGeomXformable

Transformable camera.

Describes optical properties of a camera via a common set of attributes that provide control over the camera’s frustum as well as its depth of field. For stereo, the left and right camera are individual prims tagged through the stereoRole attribute.

There is a corresponding class GfCamera, which can hold the state of a camera (at a particular time). UsdGeomCamera::GetCamera() and UsdGeomCamera::SetFromCamera() convert between a USD camera prim and a GfCamera.

To obtain the camera’s location in world space, call the following on a UsdGeomCamera ‘camera’: 

GfMatrix4d camXform = camera.ComputeLocalToWorldTransform(time);

Units of Measure for Camera Properties

Despite the familiarity of millimeters for specifying some physical camera properties, UsdGeomCamera opts for greater consistency with all other UsdGeom schemas, which measure geometric properties in scene units, as determined by UsdGeomGetStageMetersPerUnit(). We do make a concession, however, in that lens and filmback properties are measured in tenths of a scene unit rather than “raw” scene units. This means that with the fallback value of .01 for metersPerUnit - i.e. scene unit of centimeters - then these “tenth of scene unit” properties are effectively millimeters.

For any described attribute Fallback Value or Allowed Values below that are text/tokens, the actual token is published and defined in UsdGeomTokens. So to set an attribute to the value “rightHanded”, use UsdGeomTokens->rightHanded as the value.

See also

UsdGeom_LinAlgBasics

Note

Cameras in USD are always “Y up”, regardless of the stage’s orientation (i.e. UsdGeomGetStageUpAxis()). This means that the inverse of ‘camXform’ (the VIEW half of the MODELVIEW transform in OpenGL parlance) will transform the world such that the camera is at the origin, looking down the -Z axis, with +Y as the up axis, and +X pointing to the right. This describes a right handed coordinate system.

Note

If one adds a Camera prim to a UsdStage whose scene unit is not centimeters, the fallback values for filmback properties will be incorrect (or at the least, unexpected) in an absolute sense; however, proper imaging through a “default camera” with focusing disabled depends only on ratios of the other properties, so the camera is still usable. However, it follows that if even one property is authored in the correct scene units, then they all must be.

Public Functions

inline explicit UsdGeomCamera(const UsdPrim &prim = UsdPrim())

Construct a UsdGeomCamera on UsdPrim prim. Equivalent to UsdGeomCamera::Get(prim.GetStage(), prim.GetPath()) for a valid prim , but will not immediately throw an error for an invalid prim.

inline explicit UsdGeomCamera(const UsdSchemaBase &schemaObj)

Construct a UsdGeomCamera on the prim held by schemaObj . Should be preferred over UsdGeomCamera(schemaObj.GetPrim()), as it preserves SchemaBase state.

inline virtual ~UsdGeomCamera()

Destructor.

inline operator bool() const

Boolean operator.

Returns

Return true if the contained prim is an instance of this schema using IsA, and false otherwise.

inline UsdAttribute GetProjectionAttr() const

Declaration

token projection = "perspective"

C++ Type

TfToken

Usd Type

SdfValueTypeNames->Token

Allowed Values

perspective, orthographic

inline UsdAttribute CreateProjectionAttr() const

See GetProjectionAttr(), and also Create vs Get Property Methods for when to use Get vs Create. If specified, author defaultValue as the attribute’s default, sparsely (when it makes sense to do so) if writeSparsely is true - the default for writeSparsely is false.

inline UsdAttribute GetHorizontalApertureAttr() const

Horizontal aperture in tenths of a scene unit; see Units of Measure for Camera Properties . Default is the equivalent of the standard 35mm spherical projector aperture.

Declaration

float horizontalAperture = 20.955

C++ Type

float

Usd Type

SdfValueTypeNames->Float

inline UsdAttribute CreateHorizontalApertureAttr() const

See GetHorizontalApertureAttr(), and also Create vs Get Property Methods for when to use Get vs Create. If specified, author defaultValue as the attribute’s default, sparsely (when it makes sense to do so) if writeSparsely is true - the default for writeSparsely is false.

inline UsdAttribute GetVerticalApertureAttr() const

Vertical aperture in tenths of a scene unit; see Units of Measure for Camera Properties . Default is the equivalent of the standard 35mm spherical projector aperture.

Declaration

float verticalAperture = 15.2908

C++ Type

float

Usd Type

SdfValueTypeNames->Float

inline UsdAttribute CreateVerticalApertureAttr() const

See GetVerticalApertureAttr(), and also Create vs Get Property Methods for when to use Get vs Create. If specified, author defaultValue as the attribute’s default, sparsely (when it makes sense to do so) if writeSparsely is true - the default for writeSparsely is false.

inline UsdAttribute GetHorizontalApertureOffsetAttr() const

Horizontal aperture offset in the same units as horizontalAperture. Defaults to 0.

Declaration

float horizontalApertureOffset = 0

C++ Type

float

Usd Type

SdfValueTypeNames->Float

inline UsdAttribute CreateHorizontalApertureOffsetAttr() const

See GetHorizontalApertureOffsetAttr(), and also Create vs Get Property Methods for when to use Get vs Create. If specified, author defaultValue as the attribute’s default, sparsely (when it makes sense to do so) if writeSparsely is true - the default for writeSparsely is false.

inline UsdAttribute GetVerticalApertureOffsetAttr() const

Vertical aperture offset in the same units as verticalAperture. Defaults to 0.

Declaration

float verticalApertureOffset = 0

C++ Type

float

Usd Type

SdfValueTypeNames->Float

inline UsdAttribute CreateVerticalApertureOffsetAttr() const

See GetVerticalApertureOffsetAttr(), and also Create vs Get Property Methods for when to use Get vs Create. If specified, author defaultValue as the attribute’s default, sparsely (when it makes sense to do so) if writeSparsely is true - the default for writeSparsely is false.

inline UsdAttribute GetFocalLengthAttr() const

Perspective focal length in tenths of a scene unit; see Units of Measure for Camera Properties .

Declaration

float focalLength = 50

C++ Type

float

Usd Type

SdfValueTypeNames->Float

inline UsdAttribute CreateFocalLengthAttr() const

See GetFocalLengthAttr(), and also Create vs Get Property Methods for when to use Get vs Create. If specified, author defaultValue as the attribute’s default, sparsely (when it makes sense to do so) if writeSparsely is true - the default for writeSparsely is false.

inline UsdAttribute GetClippingRangeAttr() const

Near and far clipping distances in scene units; see Units of Measure for Camera Properties .

Declaration

float2 clippingRange = (1, 1000000)

C++ Type

GfVec2f

Usd Type

SdfValueTypeNames->Float2

inline UsdAttribute CreateClippingRangeAttr() const

See GetClippingRangeAttr(), and also Create vs Get Property Methods for when to use Get vs Create. If specified, author defaultValue as the attribute’s default, sparsely (when it makes sense to do so) if writeSparsely is true - the default for writeSparsely is false.

inline UsdAttribute GetClippingPlanesAttr() const

Additional, arbitrarily oriented clipping planes. A vector (a,b,c,d) encodes a clipping plane that cuts off (x,y,z) with a * x + b * y + c * z + d * 1 < 0 where (x,y,z) are the coordinates in the camera’s space.

Declaration

float4[] clippingPlanes = []

C++ Type

VtArray<GfVec4f>

Usd Type

SdfValueTypeNames->Float4Array

inline UsdAttribute CreateClippingPlanesAttr() const

See GetClippingPlanesAttr(), and also Create vs Get Property Methods for when to use Get vs Create. If specified, author defaultValue as the attribute’s default, sparsely (when it makes sense to do so) if writeSparsely is true - the default for writeSparsely is false.

inline UsdAttribute GetFStopAttr() const

Lens aperture. Defaults to 0.0, which turns off focusing.

Declaration

float fStop = 0

C++ Type

float

Usd Type

SdfValueTypeNames->Float

inline UsdAttribute CreateFStopAttr() const

See GetFStopAttr(), and also Create vs Get Property Methods for when to use Get vs Create. If specified, author defaultValue as the attribute’s default, sparsely (when it makes sense to do so) if writeSparsely is true - the default for writeSparsely is false.

inline UsdAttribute GetFocusDistanceAttr() const

Distance from the camera to the focus plane in scene units; see Units of Measure for Camera Properties .

Declaration

float focusDistance = 0

C++ Type

float

Usd Type

SdfValueTypeNames->Float

inline UsdAttribute CreateFocusDistanceAttr() const

See GetFocusDistanceAttr(), and also Create vs Get Property Methods for when to use Get vs Create. If specified, author defaultValue as the attribute’s default, sparsely (when it makes sense to do so) if writeSparsely is true - the default for writeSparsely is false.

inline UsdAttribute GetStereoRoleAttr() const

If different from mono, the camera is intended to be the left or right camera of a stereo setup.

Declaration

uniform token stereoRole = "mono"

C++ Type

TfToken

Usd Type

SdfValueTypeNames->Token

Variability

SdfVariabilityUniform

Allowed Values

mono, left, right

inline UsdAttribute CreateStereoRoleAttr() const

See GetStereoRoleAttr(), and also Create vs Get Property Methods for when to use Get vs Create. If specified, author defaultValue as the attribute’s default, sparsely (when it makes sense to do so) if writeSparsely is true - the default for writeSparsely is false.

inline UsdAttribute GetShutterOpenAttr() const

Frame relative shutter open time in UsdTimeCode units (negative value indicates that the shutter opens before the current frame time). Used for motion blur.

Declaration

double shutter:open = 0

C++ Type

double

Usd Type

SdfValueTypeNames->Double

inline UsdAttribute CreateShutterOpenAttr() const

See GetShutterOpenAttr(), and also Create vs Get Property Methods for when to use Get vs Create. If specified, author defaultValue as the attribute’s default, sparsely (when it makes sense to do so) if writeSparsely is true - the default for writeSparsely is false.

inline UsdAttribute GetShutterCloseAttr() const

Frame relative shutter close time, analogous comments from shutter:open apply. A value greater or equal to shutter:open should be authored, otherwise there is no exposure and a renderer should produce a black image.

Declaration

double shutter:close = 0

C++ Type

double

Usd Type

SdfValueTypeNames->Double

inline UsdAttribute CreateShutterCloseAttr() const

See GetShutterCloseAttr(), and also Create vs Get Property Methods for when to use Get vs Create. If specified, author defaultValue as the attribute’s default, sparsely (when it makes sense to do so) if writeSparsely is true - the default for writeSparsely is false.

inline UsdAttribute GetExposureAttr() const

Exposure adjustment, as a log base-2 value. The default of 0.0 has no effect. A value of 1.0 will double the image-plane intensities in a rendered image; a value of -1.0 will halve them.

Declaration

float exposure = 0

C++ Type

float

Usd Type

SdfValueTypeNames->Float

inline UsdAttribute CreateExposureAttr() const

See GetExposureAttr(), and also Create vs Get Property Methods for when to use Get vs Create. If specified, author defaultValue as the attribute’s default, sparsely (when it makes sense to do so) if writeSparsely is true - the default for writeSparsely is false.

inline UsdAttribute GetXformOpOrderAttr() const

Encodes the sequence of transformation operations in the order in which they should be pushed onto a transform stack while visiting a UsdStage’s prims in a graph traversal that will effect the desired positioning for this prim and its descendant prims.

You should rarely, if ever, need to manipulate this attribute directly. It is managed by the AddXformOp(), SetResetXformStack(), and SetXformOpOrder(), and consulted by GetOrderedXformOps() and GetLocalTransformation().

Declaration

uniform token[] xformOpOrder

C++ Type

VtArray<TfToken>

Usd Type

SdfValueTypeNames->TokenArray

Variability

SdfVariabilityUniform

inline UsdAttribute CreateXformOpOrderAttr() const

See GetXformOpOrderAttr(), and also Create vs Get Property Methods for when to use Get vs Create. If specified, author defaultValue as the attribute’s default, sparsely (when it makes sense to do so) if writeSparsely is true - the default for writeSparsely is false.

inline UsdAttribute GetVisibilityAttr() const

Visibility is meant to be the simplest form of “pruning” visibility that is supported by most DCC apps. Visibility is animatable, allowing a sub-tree of geometry to be present for some segment of a shot, and absent from others; unlike the action of deactivating geometry prims, invisible geometry is still available for inspection, for positioning, for defining volumes, etc.

Declaration

token visibility = "inherited"

C++ Type

TfToken

Usd Type

SdfValueTypeNames->Token

Allowed Values

inherited, invisible

inline UsdAttribute CreateVisibilityAttr() const

See GetVisibilityAttr(), and also Create vs Get Property Methods for when to use Get vs Create. If specified, author defaultValue as the attribute’s default, sparsely (when it makes sense to do so) if writeSparsely is true - the default for writeSparsely is false.

inline UsdAttribute GetPurposeAttr() const

Purpose is a classification of geometry into categories that can each be independently included or excluded from traversals of prims on a stage, such as rendering or bounding-box computation traversals.

See UsdGeom_ImageablePurpose for more detail about how purpose is computed and used.

Declaration

uniform token purpose = "default"

C++ Type

TfToken

Usd Type

SdfValueTypeNames->Token

Variability

SdfVariabilityUniform

Allowed Values

default, render, proxy, guide

inline UsdAttribute CreatePurposeAttr() const

See GetPurposeAttr(), and also Create vs Get Property Methods for when to use Get vs Create. If specified, author defaultValue as the attribute’s default, sparsely (when it makes sense to do so) if writeSparsely is true - the default for writeSparsely is false.

inline UsdRelationship GetProxyPrimRel() const

The proxyPrim relationship allows us to link a prim whose purpose is “render” to its (single target) purpose=”proxy” prim. This is entirely optional, but can be useful in several scenarios:

  • In a pipeline that does pruning (for complexity management) by deactivating prims composed from asset references, when we deactivate a purpose=”render” prim, we will be able to discover and additionally deactivate its associated purpose=”proxy” prim, so that preview renders reflect the pruning accurately.

  • DCC importers may be able to make more aggressive optimizations for interactive processing and display if they can discover the proxy for a given render prim.

  • With a little more work, a Hydra-based application will be able to map a picked proxy prim back to its render geometry for selection.

Note

It is only valid to author the proxyPrim relationship on prims whose purpose is “render”.

inline UsdRelationship CreateProxyPrimRel() const

See GetProxyPrimRel(), and also Create vs Get Property Methods for when to use Get vs Create.

UsdPrim GetPrim() const

Return this schema object’s held prim.

SdfPath GetPath() const

Return the SdfPath to this schema object’s held prim.

Public Static Functions

static inline UsdGeomCamera Define(const UsdStageRefPtr &stage, const SdfPath &path)

Attempt to ensure a UsdPrim adhering to this schema at path is defined (according to UsdPrim::IsDefined()) on this stage.

Public Static Attributes

static const UsdSchemaType schemaType = UsdSchemaType::ConcreteTyped

Compile time constant representing what kind of schema this class is.

See also

UsdSchemaType