Clears the Alembic cache and reloads fresh geometry.
Number of Layers
Use this multiparm to apply Alembic layers.
Path to the Alembic archive (
The Alembic frame at which to sample the geometry. The default value is
$F (Houdini’s current frame). If you need to offset the start time of the
animation in the archive, you can add or subtract frames (e.g.
$F + 48).
Frames per second
Combined with the Frame parameter, this is used to convert Alembic’s
time-based animation to Houdini frames. The default is
current frames-per-second setting). If the archive file was created with a
different FPS, you will need to enter it here.
What should be done if the specified file does not exist on disk. By default, if there’s a missing or invalid Alembic archive, the SOP will error. This can be troublesome in a network that can recover from the error. In these cases the behavior can be set to No Geometry so only a warning is posted.
Create Primitives For
Packed primitives can be created for shapes, transforms, or both. By default packed primitives are only created for shapes.
Shape Nodes Only
Geometry in the Alembic scene only.
Shapes and Transforms
Geometry and transforms in the Alembic scene.
Transform Nodes Only
Transforms in the Alembic scene only.
How to load the Alembic geometry into Houdini:
Alembic Delayed Load Primitives
These custom primitives are very light-weight and will display faster in the viewport. They are not as full featured as other Houdini primitive types (i.e. ray-tracing is not very accurate), but can be converted to other primitive types if need be.
Unpack Alembic Delayed Load Primitives
Load the geometry as Alembic packed primitives and then automatically unpack the geometry to create native Houdini geometry.
Load Houdini Geometry
Convert the Alembic primitives to use native Houdini geometry.
Houdini Point Cloud
P attribute from the Alembic primitives as a Houdini
point cloud. Currently, this doesn’t load any attributes other
Load only the bounding boxes of the Alembic primitives.
How the Alembic geometry is displayed in the viewport.
The Alembic geometry is fully displayed.
Only the points are displayed.
Only the geometry bounding boxes are displayed.
Only the geometry centroid is displayed.
No geometry is displayed.
When loading Alembic Delayed Load primitives, you can create an unique point for each primitive, or all the Alembic primitives can share a single point. The unique points can all be at the origin, or alternatively, located at the primitive’s centroid.
Poly Soup Primitives
When loading Houdini geometry, this option determines whether Alembic Polygon Meshes will be converted to Houdini Poly Soup primitives. Houdini Poly Soup primitives use less resources to store and render. At the current time Poly Soups cannot be rendered as subdivision surfaces by Mantra.
No Poly Soup Primitives
No polygon soup primitives will be created. Each face in a mesh will have a unique Houdini polygon primitive.
Use Poly Soups For Polygon Meshes
Create polygon soup primitives for Alembic Polygon Meshes where possible. This will currently not be done if there are uniform attributes on the mesh or if there are face sets.
Use Poly Soups Wherever Possible
Create Poly Soup primitives for both Alembic Polygon Meshes and Alembic Subdivision Surface primitives. If there are uniform attributes (per-face attributes) these will be lost.
Transform Geometry To World Space
Bake each object’s world space transformation (relative to the root of the archive) into the primitives of the object.
Use the visibility settings defined in the Alembic file to determine whether to load geometry. When loading Alembic Delayed Load primitives, hidden primitives will still be loaded, but will not create any visible geometry. There may be additional cost to using visibility with Alembic Delayed Load primitives.
Set Zero Time for Static Geometry
Set the time/frame for static geometry to 0 regardless of the frame specified. This is an optimization that lets mantra load static geometry slightly faster when there are multiple instances of the same shape node.
This option can create a large number of disjoint groups. This is often a very inefficient workflow. Instead, consider using a string attribute to store what would be your group name using Attribute Create or Attribute Wrangle.
To convert a set of disjoint groups, such as created by this option, into a single string attribute use the Name from Group option of the Name SOP.
Whether to create group names on the Alembic shape nodes, or whether to use the transform (object) name. If a transform object has multiple shape nodes, it’s sometimes useful to put the geometry into the same group.
When loading Houdini geometry, all subdivision shape nodes in the Alembic file will be added to this group.
A path to one or more objects inside the archive. If specified, the node will load only these object and their children. The default is blank, which means load all the geometry in the archive.
A path to one or more objects inside the archive. If specified, the node will skip loading these objects and their children. These exclusions override the objects specified in the Object Path. The default is blank, which means don’t exclude any objects.
Only objects matching this pattern will be loaded. This is a more generic and likely simpler way of specifying objects to be loaded than the Object Path.
This allows you to filter objects based on whether they are animated or not.
Include All Primitives (default)
Load primitives whether they are animating or static.
Only Static Primitives
Only load primitives which are not animated.
Only Deforming Primitives
Only load primitives with point positions that change over time.
Only Transforming Primitives
Only load primitives with parent transformation nodes that change over time.
Only Deforming or Transforming Primitives
Only load primitives which are animated.
This allows loading of polygons.
This allows loading of curves.
This allows loading of NURBS.
This allows loading of points.
Load Subdivision Surfaces
This allows loading of subdivision surfaces.
Load Maya Locater
Test for transform nodes which match how Maya saves out locater nodes and load these into Houdini.
This allows you to only load primitives based on their bounding box in space.
No spatial filtering (default)
Loads all primitives.
Load Objects Entirely Inside Box
Loads only objects which are entirely contained inside the specified bounding box.
Load Objects Partially Inside Box
Loads only objects whose bounding box intersects the specified bounding box.
Load Objects Entirely Outside Box
Loads only objects which are entirely outside the specified bounding box.
Load Objects Partially Outside Box
Loads only objects whose bounding box is not entirely contained in the specified bounding box.
Use First Input To Specify Box
Use the input to the Alembic SOP to specify the bounding box used for Box Culling.
Manually specify the size of the culling bounding box.
Manually specify the center of the culling bounding box
This allows you to only load primitives based on the size of their bounding box.
No size filtering (default)
Loads all primitives.
Filter Objects By Bounding Area
Loads only objects which are bounded by a box that matches the radius constraint.
Filter Objects By Bounding Radius
Loads only objects which are bounded by a sphere that matches the radius constraint.
Filter Objects By Bounding Volume
Loads only objects which are bounded by a box that matches the volume constraint.
This allows you to specify the test used when comparing each bounding box.
Loads only objects which are bounded by box smaller than the specified size.
Loads only objects which are bounded by box larger than the specified size.
Specifies the size each bounding box is compared against.
Only point attributes matching the given pattern will be loaded.
Only vertex attributes matching the given pattern will be loaded.
Only primitive attributes matching the given pattern will be loaded.
Only detail attributes matching the given pattern will be loaded.
Only faceset attributes matching the given pattern will be loaded.
All intrinsic attributes on Alembic nodes will be created in all cases. For
velocity attribute on points will be created regardless of
whether it matches the Point Attribute pattern.
How Alembic user properties should be handled.
Do Not Load
User properties are not loaded.
Load Values Only
User property values are loaded as a JSON dictionary into a primitive string attribute.
Load Values and Metadata
User property values are loaded as a JSON dictionary into a primitive string attribute. User property metadata, useful for interpreting and processing the values, is loaded as a JSON dictionary into a separate primitive string attribute.
Add Path Attribute
This option allows you to put the full path of the shape node into the named string attribute, since Houdini can mangle the group names (no special characters are allowed in group names).
The name of the Path Attribute.
Add Filename Attribute
Add a detail attribute containing the filename.
The name of the Filename Attribute.
Use this multiparm to rename Alembic point, vertex, and/or primitive
attributes to their Houdini equivalents and optionally change their type
info. For example, remapping
Cd (diffuse color). Click
the + button to add a new mapping.