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This node adds an
xformOp:transformattribute (part of the
UsdGeomXformableschema) to the selected prim(s). This is more lightweight than parenting the prim to an
Xformprim (see the Xform node).
Cooking this node can generate many USD time samples, rather than just a single time sample at the current time. This can be equivalent to having a Cache LOP following this node, but it will evaluate much faster, and does not cache data from any other nodes. This allows animated data to be authored to USD without introducing a node time dependency which would then cause all following nodes to also be time dependent. This can vastly improve playback performance of some LOP Networks.
In all sampling modes, if a parameter on this node does not vary with time, and does not rely on other time sampled data from the stage, only a single default value will be generated in USD for the corresponding attribute. USD time samples are only generated for parameters that may vary over time.
Sample Current Frame
A single time sample will be generated for the current time.
Sample Frame Range If Input Is Not Time Dependent
If the input to this node is time dependent, this node behaves as if it is in
Sample current frame mode. Otherwise it behaves as if it is in
Sample frame range mode.
Sample Frame Range
The Start/End/Inc parameter is used to generate multiple times at which this node’s parameters are evaluated, and a USD time sample is created for each attribute at each one of these times.
When the Sampling behavior is
Sample frame range, this parameter controls the number and spacing of base time samples to be generated by this node. The default values of this parameter are
@ropinc. These values correspond to the start, end, and step size of the global Houdini animation settings when interacting with Houdini. When using a ROP node to generate a range of frames, these values correspond to the start, end, and increment values specified on the ROP node being executed. This default ensures that a USD file written to disk will contain time samples for exactly the frame range requested by the ROP (regardless of the Houdini animation settings).
For each primary sample generated by this node, these parameters can cause additional samples to be generated aroudn that primary sample time. This is most often used to ensure that accurate data exists at exactly the camera shutter open and close times, as well as at the primary sample time.
Controls the method used to specify the shutter open and close times relative to the primary sample times.
The Shutter open/close parameter values provide exact offset values relative to the primary sample time.
Use Camera Prim
The Camera prim parameter provides the scene graph path of a camera primitive from which the shutter open and close times are extracted to provide the offset values relative to the primary time sample.
When the Shutter mode is
Specify Manually, these two offset values are added to the primary sample time to indicate the shutter open and close times. The open time should be less than or equal to zero, and the close time should be greater than or equal to zero.
Scene graph path of a camera prim on the input node’s stage. The shutter open and close attribute values are read from this primitive.
The number of subframe samples to create for each primary sample. These samples are evenly distributed between the shutter open and close times. Note that such an even distribution may or may not create a sample at exactly the primary sample time.
Always Include Frame Sample
Enable this option to force a sample to be created at exactly the primary sample time. If the Samples values together with the shutter open and close times already place a sample at the primary sample time, turning on this option will have no effect. Otherwise, this option will cause an addition sample to be added. This means that the actual number of samples per primary sample may in fact be one more than the number specified in the Samples parameter.
The primitive(s) the node should operate on. You can drag primitives from the scene graph tree pane into this textbox to add their paths, or click the Reselect button beside the text box to select the primitives in the viewer, or ⌃ Ctrl-click the Reselect button to choose prims from a pop-up tree window. You can also use primitive patterns for advanced matching, including matching all prims in a collection (using
Because all USD edits are non-destructive, editing transforms is accomplished adding a
xformOp:transform attribute. Each attribute name has a descriptive suffix. For example, if you set this to
foo, it authors an attribute named
xformOp:transform:foo. The resulting full attribute name must be unique among attributes on the same prim (Houdini will automatically alter the name by adding a number if it’s not unique).
The default (
$OS) uses the node name as the descriptive suffix.
Apply Transform in World Space
(Default on) Apply the given transform as if it was in world space. When this is off, the transform is local. Technically, transform operations are always local, but this can be confusing (For example, a parent prim may have a rotation around Z, which will make a local move along X axis actually move the primitive along world Y). So this option exists to let you specify the transform more intuitively in world space, and have the node create a local transform that achieves the same effect.
Set Absolute Transform
When Apply Transform in World Space is off and this is on, make this transform the only active
xformOp:transform attribute on the prim. This works by setting the
xformOpOrder list to only contain the new transform attribute. (So any previously existing transform attributes are still on the prim, but aren’t used because they're not listed in
The order in which Houdini applies translates, rotates, and scales, and the order in which it applies rotation.
Movement amount along XYZ axes.
Degrees rotation around XYZ axes.
Non-uniform scaling along XYZ axes.
Moves the local origin of the object.
Rotates the local origin of the object after translation.