Not Started

The Houdini Engine session has not been initialized yet. (the plugin only starts a session after instantiating a new HDA or modifying an existing HDA).

Ready

The Houdini Engine Session was successfully created and the plugin is actively communicating with Houdini Engine.

Stopped

The Houdini Engine session was manually interupted by the user.

Failed

The plugin was unable to start a Houdini Engine session. The logs will likely indicate the reason of the failure.

Lost

The plugin had lots contact with the Houdini Engine Session. This likely indicates that either Houdini / HARS was manually interrupted, or that it crashed.

Failed - No License

This indicates that the plugin was unable to start a Houdini Engine session due to the lack of Houdini Engine / Houdini License.

off

This indicates that the session type is set to None in the plugin settings. The plugin will not try to create a Houdini Engine session, and will not be able to instantiate/cook HDAs.

Recook

Forces the asset to recook even if no change has been detected.

Rebuild

Reimports the asset’s .hda file in and forces the asset to recook even if no change has been detected. This is useful when the underlying .hda has been updated or if something is out of sync. Rebuilding an HDA will update its interface, and any new parameter or input will be visible in the details panel. Value of existing parameter or input will be kept after a rebuild, but the input data will be recreated on the Houdini side.

Reset Parameters

Resets all of the asset’s parameters to their default state saved in the Digital Asset.

Temporary Cook Folder

Indicates the directory that will be used to save the temporary output files generated by the Houdini Asset when cooking. This can also be set via the “unreal_temp_folder” attribute.

Bake

Bake all the outputs of the Houdini Asset. The type of asset produced when baking can be control by the combo box next to the bake button.

Actor

Bake the current asset outputs to Actors in the world. Baking to Actors will bake all outputs and then spawns new individual Unreal-native actors for each outputa. The new actors will be added to a new folder in the World Outliner.

Blueprint

Bake the current asset outputs to a BluePrint Actor in the content browser. All of the Houdini Asset’s outputs are baked to .uasset files in the bake folder, and a new Blueprint Actor class is created, which has components that uses all the baked outputs.

One Actor Per Component

When on, creates individual actors for each output component in the HDA when baking.

One Actor Per HDA

When on, creates a single actor when baking an HDA with each output as an individual component of that actor.

Remove HDA output after Bake

After baking, all the temporary/cook outputs of the HDA will be automatically destroyed. This is useful when baking to Actors since it avoids having both baked and cooked outputs overlapping.

Auto Bake

When on, the temporary outputs of the Houdini Assets are automatically baked after a succesfull cook.

Recenter Baked Actors

When on, this option automatically recenters the position of all the baked Actors, making them use the center of their bounding box instead of the HDA’s location.

Replace previous Bake

When on, baking will always overwrite the previous bake’s results. When off, the baked files will be created incrementally, and will never replace previous bake files.

Bake Folder

Set the directory where baked output assets will be saved if the unreal_bake_folder attribute is not set on the output. The Bake Folder is determined by checking the unreal_bake_folder attribute first, then this setting, and lastly the default folder configured in the plugin settings. Clicking on the Browse button will open a window that will let you choose the directory, while the Reset button will restore the bake Folder to its default value.

On Parameter/Input change

When any parameter or input is changed on the HDA, a cook of the asset will be triggered. Turning this off allows parameters/inputs to be changed without recooking the ouputs. Cooking must then be performed manually by selecting Recook. This can be helpful for complex assets that have a long cooking time.

On Transform change

When on, translating, rotating, or scaling the Houdini Asset Actor in Unreal will automatically trigger a recook of the HDA.

On Asset Input Cook

When using another HDA in a World Input, this option lets you decide if this HDA should be recooked automatically when its input HDA is cooked (after modifying its parameters or inputs).

Push transform to Houdini

When on, sets the Unreal world transform on the digital asset’s input node in Houdini.

Temp Landscape Layers

Allows you to preview the cooked data in a separate layer. This is useful when modifying an Edit Layer on an existing Landscape, as writing to an Edit Layer is destructive and changes can’t be undone easily.

Do not generate outputs

Prevents the Houdini Asset from generating outputs. The asset will be cooked in Houdini but will not produce anything in Unreal. This can be useful when chaining multiple Houdini Assets together using Asset Inputs.

Use Output Nodes

When on, the plugin uses the HDA’s output nodes to produce the cook result. When off, the plugin uses the node that has the display flag on to produce the HDA’s outputs.

Use Templated Geos

When on, outputs will be created for templated nodes found in the HDA. Templated outputs are editor-only and use a wireframe material. This can be useful as a visualizer (ex. a cutting plane) directly in the Unreal Editor.

Show Cook log

Displays the contents of the Houdini cook log. This is useful for troubleshooting/debugging the Digital Asset.

Asset Help

Displays the contents of the Digital Asset help. The help is created via the Help tab in the Operator Type Properties window for the Digital Asset in Houdini.

Keep World Transform

Controls the way the geometry’s transform is used in Houdini. When on, the Unreal Transform will be used in Houdini. When off, the Unreal Transform will be ignored in Houdini, treating the geometry at the origin.

Pack Geometry before merging

When on, individual packed primitives will be created for each input object. When off, all the input objects will be merged into a single geometry.

Export Input as References

When on, the input object’s full geometry will not be exported to Houdini. Instead, they will be exported as a point with the unreal_instance ref set to the object reference, and with additional information like transform, materials, and bounding box size.

Export LODs

Export all the LODs meshes found in the asset to Houdini. Each LOD mesh will be available in a separate group.

See Level of Details for more information.

Export Sockets

Export all the mesh sockets found in the asset to Houdini. See Mesh Sockets for more information.

Export Colliders

Exports all the simple colliders found in the asset to Houdini as grouped geometry, using the correspond unreal_collision_ groups.

Export Material Paramaters

Exports all the material parameters found in the asset’s materials as attributes. This option can be costly on large meshes that have multiple materials with a lot of exposed parameters.

Merge Spline Mesh Components

When on, spline mesh components in the input will be merge into a single static mesh.

Prefer Nanite Fallback Mesh

When on, Nanite fallback meshes will be used for the input asset instead of the full Nanite geometry.

Add

Creates extra input slots that can be used to import multiple assets.

Clear All

Deletes and empties all the current inputs slots.

Keep World Transform

Controls the way the geometry’s transform is used in Houdini. When on, the Unreal Transform will be used in Houdini. When off, the Unreal Transform will be ignored in Houdini, treating the geometry at the origin.

Pack Geometry before merging

When on, individual packed primitives will be created for each input object. When off, all the input objects will be merged into a single geometry.

Export Input as References

When on, the input object’s full geometry will not be exported to Houdini. Instead, they will be exported as a point with the unreal_instance ref set to the object reference, and with additional information like transform, materials, and bounding box size.

Export LODs

Export all the LODs meshes found in the asset to Houdini. Each LOD mesh will be available in a separate group. See Level of Details for more information.

Export Sockets

Export all the mesh sockets found in the asset to Houdini. See Mesh Sockets for more information.

Export Colliders

Exports all the simple colliders found in the asset to Houdini as grouped geometry, using the correspond unreal_collision_ groups.

Export Material Paramaters

Exports all the material parameters found in the asset’s materials as attributes. This option can be costly on large meshes that have multiple materials with a lot of exposed parameters.

Merge Spline Mesh Components

When on, spline mesh components in the input will be merge into a single static mesh.

Prefer Nanite Fallback Mesh

When on, Nanite fallback meshes will be used for the input asset instead of the full Nanite geometry.

Directly Connect HDAs in Houdini

When on, Houdini Asset Actors in the selection will be directly connected in Houdini to this HDA. When off, the Houdini Actor’s Unreal output will be sent to Houdini.

Use Legacy Input Curves

When on, the plugin will automatically create curve::1.0 nodes for spline inputs. This can be useful for backward compatibility with older HDAs that relied on the curve node.

Unreal Spline Resolution

Controls the sample length used to resample Unreal splines. The default value of 50 will extract a spline point every 50cm in Unreal and export it to Houdini. If set to 0, only the spline’s control point will be exported.

Export Height Data Per Edit Layer

Exports the height data for each edit layer. Turn off to improve performance.

Export Paint Layers Per Edit Layer

Exports each paint layer for each edit layer. Turn off to improve performance.

Export Merged Paint Layers Per Landscape

Exports a single paint layer of all edit layers' paint layers into one.

Export Selected Landscape Components Only

When on, only the selected landscape component will be exported.

Export Landscape as

Controls how Landscapes are exported in Unreal: as Heightfield, as Mesh or as a Point cloud.

Export Landscape Materials

The landscape’s face and hole materials will be exported to Houdini.

Export Landscape Tile UV

The landscape’s UVs will be exported in a separate texture for each tile.

Export Landscape Normalized UVs

The landscape’s UV values will be exported in 0, 1.

Export Landscape Lighting

The landscape’s UVs will be exported in a separate texture for each tile.

Export Landscape Spline Control Points

When on, the control points of Landscape splines will be exported as a point cloud in Houdini.

Export Landscape Spline Left / Right Curves

When on, the left and right curve of the landscape spline will be exported to Houdini.

Export Spline Mesh Components

When on, the Landscape Spline’s mesh component will also be exported to Houdini.

Auto Select Landscape Spline For Export

When on, any Landscape selected by the input will automatically export its Landscape Splines to Houdini.

Use Bound Selector

When on, the selected Actors will acts as bound selectors: any Actors within their bounding box will be exported to Houdini.

Start Selection/Use Current

This selection will lock the details panel and allow you to start selecting actors to be exported using the World Input. Selecting Use Current will unlock the details panel and use the selected actors for the input.

Clear Selection

Clears and empties the current selection.

Keep World Transform

Controls the way the geometry’s transform is used in Houdini. When on, the Unreal Transform will be used in Houdini. When off, the Unreal Transform will be ignored in Houdini, treating the geometry at the origin.

Auto Update

When on, a cook will be automatically triggered everytime you update the curve. When off, prevents cooks when the curve is modified. This lets you move thte contgrol without being interrupted.

Add Rotation/Scale Attributes

When on, adds rotation and scale attributes for each of the control point of the curve. This can be useful to turn off when working with older HDAs or nodes that do not support curves with rotation and scale attributes.

Use Legacy Input Curves

When on, the plugin will automatically create curve::1.0 nodes for spline inputs. This can be useful for backward compatibility with older HDAs that relied on the curve node.

Add

Create extra curves.

Clear All

Clears all curves created by ths input.

Reset Offset

Resets the incremental position offset that is used when creating extra curves.

Closed

Decide if the curve’s last point should be connected to the curves first points.

Reversed

Reverse the order of the curve’s control points, and can be usefull to invert the direction of the curve, or the winding of the curve’s polygon when closed.

Visible

Shows or hides the curve in the viewport.

Curve Type

Choose the curve type between Polygon (linear), NURBS, Bezier, or Points.

Curve Method

Choose the way the curve’s CV are used when using either Bezier or NURBS curves.

If CVs is selected, the curve point will be treated as Control Vertices, so the NURBS and Bezier curves will not pass through them.

If set to Breakpoints, Houdini will automatically calculate the appropriate Control Vertices so that Bezier and NURBS curves pass through the curve’s control point.

The Freehand method should be ignored in the Unreal plug-in.

Bake To Actor

Bake the curve’s HoudiniSplineComponent to a new actor with a SplineComponent.

Bake To BP

Bake the curve’s HoudiniSplineComponent to a new Blueprint with a SplineComponent.

Spline Point Editor

Displays similar controls than Unreal spline component, that lets you manually edit the transform for the currently selected control point(s).