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Interface improvements

  • Scene Graph Tree can enable or disable “Panes Follow Current Node” behavior. This button is a shortcut for the preference with the same name.

  • Render Region tool added to Solaris viewport.

  • Scene Graph Tree and Scene Graph Details highlight the row sitting beneath the mouse cursor.

New nodes

Scene assembly and layout

  • Asset Reference will detect when a USD asset’s up axis is different from the current Houdini scene, and automatically rotate the asset and align it with the world up axis.

  • Simple Merge style added to the Merge LOP, and is now the default. This new mode flattens all LOP-authored layers into the active layer, making all sublayers from disk or from SOPs weaker than this combined LOP layer.

  • Instancer LOP sets 'group' kind by default, and also excludes creating primvars for the instancing attributes (@P, @N, @up, and @orient)

  • Layout now has Stack and Paint brushes.

  • Layout LOP can also edit existing point instancers.

  • Renamed Edit Prototype to Assign Prototypes, clarifying its function of switching the prototypes used by an instance.

  • Component Output has a second input, for providing a camera and lights when generating thumbnails.

    • Supports gathering external non-USD files into the output directory with the new “Localize Assets” output processor.

  • Component Material is much more interactive, especially for heavier shader counts coming from the second input. Simple cases (~10 shaders) are 25-50% faster, and more complex shading networks (~700 shaders) improve 14x, when compared to Houdini 19.

Look Development

  • Material Library is much more efficient translating nested subnetworks of VOP nodes.

Rendering, Caching, and Export


See What’s new in Karma for general changes and fixes to Houdini’s Karma renderer and MaterialX shading support.

  • Initial “preview” version of the Karma User Guide, a guide to using and optimizing Houdini’s Karma renderer.

  • Camera LOP now has a dedicated Aspect Ratios menu, instead of re-using the existing resolution menu.

  • Many LOP nodes can now cache multiple time-samples in a single cook. This reduces the number of Houdini time dependencies, and makes USD exports, renders, and interactivity generally faster. Affected nodes include the Transform and Edit Properties LOPs. The speedup also applies to assets that use Edit Properties.

  • USD ROP and USD Render ROPs now emit a standard set of context options, which can be used in node networks to control behavior when exporting. These can sometimes be used instead of the traditional Houdini frame variables, to avoid introducing Houdini time dependencies.

  • USD Render ROP presents more options available to the husk command line tool, such as overriding resolution and enabling legacy EXR mode.

  • New Output Processor added, to allow localizing non-USD assets (texture maps, VDB files, etc…) to a specific directory.

SOP geometry import/export

  • Scene Import now translates SOP-level material assignments.

  • SOP Import has a new Bind Materials parameter. This post-process converts @usdmaterialpath attributes on the imported prims into direct material bindings.

  • Added a control to disable prefixing any created geomsubsets with the string attribute’s name.

  • Errors from the referenced SOP node are propagated to the SOP Import LOP.

  • @usdactive attribute can be used to set activate state of a primitive in SOPs.

  • SOP Modify LOP is clearer when static or animated time samples are being imported into SOPs.

  • SOP Import now uses the agent’s rest pose for the USD skeleton’s rest Transforms attribute.


  • In primitive pattern syntax, some %bound(), %closerthan(), %fartherthan(), and %visible() now take a time argument to compute membership at a specific time (to take account for animated properties such as visibility).

  • You can now use %type() to match an applied API Schema.

What’s new in Houdini 19.5