|On this page|
This node is similar to the Sublayer LOP, which imports a layer from disk and overlays it on the current scene graph tree. However, while Sublayer points to the layer on disk, this node creates a new anonymous in-memory layer, and loads the contents of the disk file into this new active layer (so it will not be saved by default). The process of bringing the layer from disk into memory can be considerably more expensive than simply reading the data from disk, so this node should only be used when it’s special capabilities of editing the loaded layer are required.
This can be useful to load a layer file, edit it, and save out a modified copy, without dealing with recursion issues. This node will often be used in a “one-off” network that only exists to load the file, perform some “surgery”, and save it out again. After that the network can be deleted.
If you load a layer file using Load Layer and modify it, you should save it out under a different name. If you save to the same file, the save operation will cause Houdini to reload the source layer, and the operations performed by nodes following this one will now be acting on a file that already has those edits applied. This may result in the double-application of some edits (such as transforms or applying deltas to attribute values), or a wasted re-application of other edits (setting attributes to specific values).
In USD, to edit a layer on disk in-place, you would set your Edit Target to the layer from disk, and perform modifications to the stage as usual. The edits would be recorded against the layer from disk. If that layer is loaded into multiple stages at the same time, all the stages would see the edit applied immediately. This would break the Solaris procedural paradigm, where all changes are the result of a node cooking.
Instead of the Edit Target, Solaris provides the Load Layer approach of copying the contents of the layer from disk into a unique, safely editable anonymous layer.
When this option is on (the default), the payload loading configuration of the input stage is not changed. When this option is off, the stage’s load mask will be modified to turn off all payload loading. Note that this will affect the loading of payloads anywhere in the stage, not just payloads loaded by the sublayers added by this node. Use the Configure Stage LOP to have more control over which payloads are loaded on the stage.
Copy Layer Metadata to Stage Root Layer
Layer metadata is not composed by USD following the normal rules. In order for values like the frames per second or up axis settings to apply to a USD stage, they must be set directly on the root layer of the stage. This means any layer metadata authored on a file being loaded by this node will not affect the stage level metadata. This options allow for the explicit copying of layer metadata from the first layer loaded by this node on to the stage’s root layer. If multiple files are specified, it it always the first file that has its values copied to the root layer.
Auto option for this parameter acts like a
Yes (copy the sublayer’s metadata to the root layer) if there is no input connected to the first input of this node. Otherwise it behaves as a
No (does not affect the stage’s root layer metadata).
The file path to the USD layer file on disk you want to copy into a new anonymous layer.
Handle Missing Files
What this node does if the file points to another file that doesn’t currently exist.
Error for Missing Files
This node errors. All cooking stops at this point and nodes connected to this node’s output will also error.
Warn for Missing Files
This node shows a warning and passes through the input unchanged.
Ignore Missing Files
Silently pass through the input unchanged.
Allow Missing Files on the Stage
Act as if the missing file was found, but empty.
Click to force a reload of the file(s) from disk.
New File Path
The file path metadata of the newly created layer. Sending the layer through the USD render node will save it to this file path.