Houdini 20.0 Nodes Geometry nodes

Object Merge geometry node

Merges geometry from multiple sources and allows you to define the manner in which they are grouped together and transformed.

Parameters

Number of Objects

The number of object merge parameters available.

Enable Merge n

Controls whether the node uses this line. This can be useful if you only want to temporarily disable a merge instead of removing it completely.

Object n

A path to the geometry to merge. You can click the chooser button to pick a node, or manually type the path.

Tip

You can use __display_sop__ or __render_sop__ in the path instead of the name of a real surface node name to have Houdini use whatever node has the display flag or render flag.

See the surface node help for an explanation of display and render flags.

  • Choose an object to merge in the object’s geometry. For example, obj/model1. Houdini uses the SOP with the display flag for display and the SOP with the render flag for rendering.

  • Use wildcards to merge in multiple objects. For example, /obj/ball* would merge in geometry from any objects whose names start with ball. The wildcards available are the same as in the opglob command.

  • Use a bundle reference (for example, @props) to merge in the geometry from all objects in a bundle.

  • Choose a SOP node to merge in that node’s geometry, even if it doesn’t have the display flag.

  • Use a dynamics path to merge in geometry from a dynamics simulation. For example, /obj/dopnet1:wireobject1/Geometry.

  • If the path is blank, Houdini doesn’t merge in any geometry.

Group n

A group of primitives within the object to merge in. Leave this blank to merge in the entire object.

Expand Group n

When Group n is not blank, turn this option on to merge in an extra ring of primitives. This is useful for maintaining the correct seam when merging in polygon primitives that are to be subdivided.

Transform

The source geometry can be transformed to account for differences between the source object’s orientation and a reference orientation. None will prevent any corrective transform from being done. Into This Object will ensure the object has difference between the source object and this object’s transforms applied. Into Specified Object will use the specified transform object rather than this object as the destination space.

Transform Object

Merged geometry will be transformed relative to the geometry defined in this field.

  • Leave the field blank to import the geometry into the current object’s space. The geometry will appear at the origin with no transformation.

  • Enter . to import the geometry using the transforms from the source object. The geometry will appear in its original position and orientation, but with zeroed transforms.

  • Enter the path of another object to import the geometry in the context of that object.

Invert Transform

If you specify a Transform Object, the geometry will be transformed from the source object’s space into the space of the given object’s space. Turning this checkbox on will reverse the transform, so the geometry will be transformed from the space of the given object to the transform of the source object.

Create Point Groups

Creates a point group for every object that is merged in. Each group name is made unique by appending a number if necessary.

Point Group Prefix

When generating names for new point groups containing the imported geometry, add this prefix. This makes it easier to identify the groups created by this merge.

Create Primitive Groups

Creates a primitive group for every object that is merged in. Each group is made unique by appending a number if necessary.

Primitive Group Prefix

When generating names for new primitive groups containing the imported geometry, add this prefix. This makes it easier to identify the groups created by this merge.

Verbose Group Names

Rather than identifying the groups with numbers, they are identified using a verbose path to the source.

Add Suffix to First Group

When identifying groups with a number, the first group does not gain the 0 suffix but is stored unmodified. This allows a single merge to be explicitly named with the group prefix. Note that if the prefix is blank, this will mean no group is created for the first merge as it will have a blank group name.

Create Per-Point Path

Creates an attribute on the imported points, containing the full path to the source from which the point was merged in. If a point is merged from DOPs , the path is the path to the DOP Geometry Data.

Create Per-Primitive Path

Creates an attribute on the imported primitives, containing the full path to the source from which the primitive was merged in. If a primitive is merged from DOPs , the path is the path to the DOP Geometry Data.

Path Attribute

The name of the per-point or per-primitive attribute created when adding primitive paths.

This defaults to objname and can be referenced in later primitive expressions using OBJNAME.

Pack Geometry Before Copying

Pack the input geometry into an Embedded Packed primitive before copying. This results in the input geometry being shared by each copy rather than being duplicated for each copy.

Pivot Location

Specifies how to initialize the offset for the point referenced by the packed primitive.

Display As

The viewport LOD for the specified packed primitives.

Add Path Attribute

This option allows you to put the full path of the merged geometry into the named string attribute.

See also

Geometry nodes