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The Retime SOP provides a friendly interface for retiming its input geometry according to the given playback speed or time function. For requested times that correspond to non-integer frames of the input geometry, this operator can perform the necessary interpolation to approximate intermediate results. This is useful to control the playback speed of a cached pyro simulation.
Time-dependent geometry to retime.
Input geometry, evaluated/interpolated at the appropriate time.
Controls how the evaluation times are computed for generating the output.
Output corresponds to evaluation of the input geometry at the given Frame.
Output corresponds to evaluation of the input geometry at the given Time.
Evaluation time is calculated from the specified Start Frame and playback Speed.
Input Frame Range is shifted to start at the specified frame.
Input Frame Range is uniformly expanded/contracted to the Output Frame Range.
Frame to evaluate the input at; only available when Evaluation Mode is set to By Frame.
Time to evaluate the input at; only available when Evaluation Mode is set to By Time.
First output frame (per Output Frame Range) corresponds to evaluation of the input at this frame. Only available when Evaluation Mode is set to By Speed.
Controls the playback speed when evaluating By Speed. Pace of playback can be varied by animating this parameter.
Shift to Frame
Input Frame Range is shifted to start at this frame when Evaluation Mode is set to Shift Range.
Output Frame Range
When evaluating By Speed, playback Speed is considered inside this frame range; boundary conditions control behavior outside of the range. When Evaluation Mode is set to Fit Range, Input Frame Range is uniformly expanded or contracted to span this range.
Input Frame Range
Range of input frames. Boundary conditions are called upon if the input must be queried outside of this range.
Boundary conditions are used to control the behavior when evaluation frame falls outside of the relevant range. The conditions always apply to the Input Frame Range, but are only available for the output range when evaluating By Speed.
Hold: clamp evaluation to the respective range limit.
Extend: allow free evaluation beyond the limit.
When evaluating By Speed, an Extend condition on the Output Frame Range will use the Speed value at that limiting frame to extrapolate outside of the range. For example, if Output Frame Range is set to
10-20with Pre-Extend, and Speed at frame 10 is set to 5, the node will assume playback speed is 5 for all frames before 10.
Cycle: wrap to the other end of the range.
Zig-Zag: upon hitting the limit, turn around and continue.
Number of available substeps in the input. This node interpolates between
closest input samples to the desired output, taking these Substeps into
account. For example, if frame
17.68 needs to be evaluated and
Substeps is set to 2, input frames
18 will be blended to
produce the result.
Interpolate Between Input Frames
Allows interpolation of input geometry from the nearest integer frames. If this option is disabled, the input is directly cooked at fractional frames.
Interpolate Rotations of Normals, Quaternion, and Transforms
Use spherical linear interpolation for smoother transitions of attributes marked as normals, quaternions, and transforms.
Interpolation method for blending multiple inputs.
Data will be linearly interpolated between 2 nearest frames.
Data will be cubically interpolated between 4 input frames where possible.
Data will follow a cubic spline curve (based on subdivision curves) between 4 input frames where possible.
Difference in time between adjacent input frames. This value is needed to correctly interpret velocities.
Use Velocity When Interpolating Position
If points have a velocity attribute (
v), enabling this option cubically
interpolates the point position using the velocity and quadratically
interpolates the velocity. The velocity attribute is also properly scaled
to account for the playback speed.
If enabled, velocities in the output are scaled to account for difference
in playback speeds. This applies to the
v point attribute as well as the
Velocity Field if volume Blend Mode is set to Advected.
A space-separator list of names/patterns for attributes to linearly interpolate. Attributes that don’t match here are switched instantly when the source interpolation frames change.
Point ID Attribute
Value of this (string or integer) point attribute is used to match points, instead of the point number.
Primitive ID Attribute
Value of this (string or integer) primitive attribute is used to match primitives, instead of the primitive number.
Primitive matching convention also applies to volumes and VDBs.
Specifies the method used to blend voxels of the volume or VDB primitives.
Volume transforms are interpolated; no blending of voxel data is performed.
By Grid Index
Voxel values are linearly interpolated; the voxels are paired by their number, so matching volumes should have the exact same dimensions and resolution.
By Voxel Position
Voxel values are linearly interpolated; the voxels are matched by their spatial position.
Voxel values are linearly interpolated along motion paths, as governed by the Velocity Field.
Name of velocity field used to deduce travel paths in Advected blending
mode. The referenced primitive must be a vector VDB or a triplet of scalar
volumes or VDBs (whose components are suffixed with
Maximum timestep used for computing travel curves. Lower values of this parameter may yield better advected interpolation, at the cost of longer running times.
Interpolate Velocity Field
When Voxel Blend is set to Advected, the Velocity Field is normally left untouched. Enabling this parameter also linearly interpolates the Velocity Field.