Create a Perspective Camera

You can define a new camera on a stage using UsdGeom.Camera. The Camera prim has a projection attribute that can be set to perspective.

USD Python

With the USD API, you can use UsdGeom.Camera.CreateProjectionAttr() to create the projection attribute and then set the value with Usd.Attribute.Set().

from pxr import Usd, Sdf, UsdGeom

def create_perspective_camera(stage: Usd.Stage, prim_path: str="/World/MyPerspCam") -> UsdGeom.Camera:
    camera_path = Sdf.Path(prim_path)
    usd_camera: UsdGeom.Camera = UsdGeom.Camera.Define(stage, camera_path)
    usd_camera.CreateProjectionAttr().Set(UsdGeom.Tokens.perspective)
    return usd_camera


#############
# Full Usage
#############

# Create an in-memory Stage with /World Xform prim as the default prim
stage: Usd.Stage = Usd.Stage.CreateInMemory()
default_prim = UsdGeom.Xform.Define(stage, Sdf.Path("/World"))
stage.SetDefaultPrim(default_prim.GetPrim())

# Create the perspective camera at /World/MyPerspCam
cam_path = default_prim.GetPath().AppendPath("MyPerspCam")
camera = create_perspective_camera(stage, cam_path)

# Export the complete Stage as a string and print it.
usda = stage.GetRootLayer().ExportToString()
print(usda)

# Check that the camera was created
prim = camera.GetPrim()
assert prim.IsValid()
assert camera.GetPath() == Sdf.Path(cam_path)
assert prim.GetTypeName() == "Camera"
projection = camera.GetProjectionAttr().Get()
assert projection == UsdGeom.Tokens.perspective

Here is how to you can set some other common attributes on the camera:

from pxr import Usd, Sdf, UsdGeom

def create_perspective_35mm_camera(stage: Usd.Stage, prim_path: str="/World/MyPerspCam") -> UsdGeom.Camera:
    camera_path = Sdf.Path(prim_path)
    usd_camera: UsdGeom.Camera = UsdGeom.Camera.Define(stage, camera_path)
    usd_camera.CreateProjectionAttr().Set(UsdGeom.Tokens.perspective)
    usd_camera.CreateFocalLengthAttr().Set(35)
    # Set a few other common attributes too.
    usd_camera.CreateHorizontalApertureAttr().Set(20.955)
    usd_camera.CreateVerticalApertureAttr().Set(15.2908)
    usd_camera.CreateClippingRangeAttr().Set((0.1,100000))
    return usd_camera


#############
# Full Usage
#############

# Create an in-memory Stage with /World Xform prim as the default prim
stage: Usd.Stage = Usd.Stage.CreateInMemory()
default_prim = UsdGeom.Xform.Define(stage, Sdf.Path("/World"))
stage.SetDefaultPrim(default_prim.GetPrim())

# Create the perspective camera at path /World/MyPerspCam with 35mm
# set for the focal length.
cam_path = default_prim.GetPath().AppendPath("MyPerspCam")
camera = create_perspective_35mm_camera(stage, cam_path)

# Export the complete Stage as a string and print it.
usda = stage.GetRootLayer().ExportToString()
print(usda)

# Check the camera attributes
focal_len = camera.GetFocalLengthAttr().Get()
assert focal_len == 35.0
clip_range = camera.GetClippingRangeAttr().Get()
assert clip_range == (0.1,100000)

Python Kit Commands

The CreatePrimWithDefaultXform command in Kit can create a Camera prim and you can optionally set camera attributes values during creation. You must use the attribute token names as the keys for the attributes dictionary. In Omniverse applications, you can explore the names by hovering over a property label in the Property Window and reading it from the tooltip.

import omni.kit.commands
from pxr import UsdGeom


def create_perspective_camera(prim_path: str="/World/MyPerspCam"):
    """Create a perspective camera

    Args:
        prim_path (str, optional): The prim path where the camera should be created. Defaults to "/World/MyPerspCam".
    """

    omni.kit.commands.execute("CreatePrimWithDefaultXform",
       prim_type="Camera",
       prim_path=prim_path,
       attributes={
           "projection": UsdGeom.Tokens.perspective,
           "focalLength": 35,
           "horizontalAperture": 20.955,
           "verticalAperture": 15.2908,
           "clippingRange": (0.1, 100000)
       }
    )


#############    
# Full Usage
#############
import omni.usd


# Create a perspective camera at /World/MyPerspCam
path = "/World/MyPerspCam"
create_perspective_camera(path)

# Check that the camera was created
stage = omni.usd.get_context().get_stage()
prim = stage.GetPrimAtPath(path)
assert prim.IsValid() == True
assert prim.GetTypeName() == "Camera"
projection = prim.GetAttribute("projection").Get()
assert projection == UsdGeom.Tokens.perspective

USDA

This is an example USDA result from creating a Camera and setting the projection to perspective. All other Properties are using the default values from the UsdGeomCamera schema definition.

#usda 1.0
(
    defaultPrim = "World"
)

def Xform "World"
{
    def Camera "MyPerspCam"
    {
        token projection = "perspective"
    }
}