def get_world_to_view_transform(self, **kwargs) -> Transform3d:
"""
Return the world-to-view transform.
Args:
**kwargs: parameters for the camera extrinsics can be passed in
as keyword arguments to override the default values
set in __init__.
Setting R and T here will update the values set in init as these
values may be needed later on in the rendering pipeline e.g. for
lighting calculations.
Returns:
T: a Transform3d object which represents a batch of transforms
of shape (N, 3, 3)
"""
R = self.R = kwargs.get("R", self.R) # pyre-ignore[16]
T = self.T = kwargs.get("T", self.T) # pyre-ignore[16]
if T.shape[0] != R.shape[0]:
msg = "Expected R, T to have the same batch dimension; got %r, %r"
raise ValueError(msg % (R.shape[0], T.shape[0]))
if T.dim() != 2 or T.shape[1:] != (3,):
msg = "Expected T to have shape (N, 3); got %r"
raise ValueError(msg % repr(T.shape))
if R.dim() != 3 or R.shape[1:] != (3, 3):
msg = "Expected R to have shape (N, 3, 3); got %r"
raise ValueError(msg % R.shape)
# Create a Transform3d object
T = Translate(T, device=T.device)
R = Rotate(R, device=R.device)
world_to_view_transform = R.compose(T)
return world_to_view_transform
def get_world_to_view_transform(R=r, T=t) -> Transform3d:
"""
This function returns a Transform3d representing the transformation
matrix to go from world space to view space by applying a rotation and
a translation.
Pytorch3d uses the same convention as Hartley & Zisserman.
I.e., for camera extrinsic parameters R (rotation) and T (translation),
we map a 3D point `X_world` in world coordinates to
a point `X_cam` in camera coordinates with:
`X_cam = X_world R + T`
Args:
R: (N, 3, 3) matrix representing the rotation.
T: (N, 3) matrix representing the translation.
Returns:
a Transform3d object which represents the composed RT transformation.
"""
# TODO: also support the case where RT is specified as one matrix
# of shape (N, 4, 4).
if T.shape[0] != R.shape[0]:
msg = "Expected R, T to have the same batch dimension; got %r, %r"
raise ValueError(msg % (R.shape[0], T.shape[0]))
if T.dim() != 2 or T.shape[1:] != (3, ):
msg = "Expected T to have shape (N, 3); got %r"
raise ValueError(msg % repr(T.shape))
if R.dim() != 3 or R.shape[1:] != (3, 3):
msg = "Expected R to have shape (N, 3, 3); got %r"
raise ValueError(msg % repr(R.shape))
# Create a Transform3d object
T = Translate(T, device=T.device)
R = Rotate(R, device=R.device)
return R.compose(T)