Houdini 20.5 Houdini Engine for 3ds Max

Data Marshalling

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Houdini Engine for 3ds Max is capable of marshalling data between Houdini and3ds Max. This section will provide a description of both the inputs (from 3ds Max to Houdini) and the outputs (from Houdini to 3ds Max) that the plugin is capable of marshalling between the two programs.

Mesh Inputs

This section describes the data that gets marshalled into Houdini when you provide any geometry input to an HDA. The 3ds Max Input column explains what the input is. The Houdini Attribute column provides the name of the attribute within Houdini that gets used for the input. The Attribute Type column indicates whether it is a point, vertex, primitive, or detail attribute. The Description column is used for any additional information.

3ds Max Input

Houdini Attribute

Attribute Type

Description

Normals

N

Vertex

Standard normal marshalling

Smoothing Groups

hemax_sg

Primitive

Marshalls the smoothing groups for the mesh’s faces

UV Layers

uv...uv99

Vertex

The plugin will marshall any UV layers that it finds. The first UV layer is placed in the uv layer, and any subsequent uv layers are appended with a number indicating the layer

Soft Selection

soft_selection

Point

Marshalls any soft selections the user has made

Colors

Cd

Vertex or Point

Marshalls any vertex colors. This will be placed in either a vertex or point attribute depending on if the number of color inputs equals the number of points or equals the number of vertices

Alpha

Alpha

Vertex or Point

Marshalls any vertex alpha values. This will be placed in either a vertex or point attribute depending on if the number of alpha inputs equals the number of points or equals the number of vertices

Illumination

illumination

Vertex or Point

Marshalls any illumination values. This will be placed in either a vertex or point attribute depending on if the number of illumination inputs equals the number of points or equals the number of vertices

Material ID

hemax_matid

Primitive

Marshalls the 3ds Max material ID for each face

Material Path

hemax_material

Primitive

If there is a material on the input, this will marshall the material path. When the material is a multi-material, this attribute will store the name of the sub-material that is applied to the mesh face

Material Path

hemax_material

Detail

If the input object has a multi-material applied, this attribute will contain the name of the multi-material. The names of the sub-materials will be stored in the hemax_material primitive attribute

Node Name

hemax_node_name

Detail

The 3ds Max node name

Mesh Input Groups

Additionally, the plugin will marshal some data into Houdini as groups:

3ds Max Input

Group Name

Group Type

Description

Group

See the description

Point

If the 3ds Max node belongs to a group, a point group will be created with the same name as the most immediate head group node

Vertex Selection

hemax_vertex_selection

Point

Group membership indicates whether the point (vertex in 3ds Max) is selected in 3ds Max. 1 indicates that the point is selected, and 0 indicates that the point is not selected

Face/Element Selection

hemax_face_selection

Primitive

Group membership indicates whether the primitive (face in 3ds Max) is selected in 3ds Max (either individually as a face or as a subset of an element selection). 1 indicates that the primitive is selected, and 0 indicates that the primitive is not selected

Edge Selection

hemax_edge_selection

Point

Edge selections must currently be sent to Houdini as a point group, which can then be promoted to a proper edge group by an HDA. Group membership indicates whether the point (vertex in 3ds Max) belongs to a selected edge in 3ds Max. 1 indicates that the point is part of a selected edge, 0 indicates that the point is not part of a selected edge

Mesh Outputs

This section describes the data that gets marshalled into a 3ds Max polygonal mesh from Houdini. The Houdini Attribute column indicates the name of the attribute that the plugin will look for when creating the display geometry. The Attribute Type column indicates what type of attribute that attribute can be. The 3ds Max Output column indicates where that attribute will be used. The Description column is used for any additional information.

Houdini Attribute

3ds Max Output

Attribute Type

Description

N

Specified Vertex Normals

Vertex

Standard normal marshalling

uv, uv2...uv99

UV Map

Vertex or Point

The plugin will create a UV map for each UV layer

hemax_sg

Smoothing Groups

Primitive

Creates smoothing groups on each face of the 3ds Max mesh

hemax_matid

Material IDs

Primitive

Creates material IDs on each face of the 3ds Max mesh

Cd

Color Map

Vertex or Point

The plugin will create a color map. The number of faces in the map will always match the number of faces in the mesh. The number of vertices in the map will either be the number of points or the number of vertices (depending on if it is a vertex or point attribute)

Alpha

Alpha Map

Vertex or Point

The plugin will create an alpha map. The number of faces in the map will always match the number of faces in the mesh. The number of vertices in the map will either be the number of points or the number of vertices (depending on if it is a vertex or point attribute)

Illumination

Illumination Map

Vertex or Point

The plugin will create an illumination map. The number of faces in the map will always match the number of faces in the mesh. The number of vertices in the map will either be the number of points or the number of vertices (depending on if it is a vertex or point attribute)

hemax_material

Assigned material on object

Detail

This allows you to specify the material to assign the object. See the Materials section for more information

hemax_node_name_output

INode Name

Detail or Primitive

The name of the outputted 3ds Max INode will be overridden with the value of this detail attribute. This attribute can also be used as a primitive attribute to override the node name of geometry created from packed primitives

hemax_bake_layer_name

Layer Name

Detail

The value of this attribute overrides the default name of the scene layer that gets created when baking a geometry HDA

hemax_bake_parent_node_name

Node Name

Detail

When baking a geometry HDA, the value of this attribute overrides the default name of the baked parent node

meta_*

User Defined Properties

Detail

This detail attribute prefix can be used to create user defined properties on the 3ds Max object. Any detail attributes with this prefix will be added, with the attribute name and value forming the key/value pair of the user defined property

Mesh Output Groups

Additionally, the plugin will marshal some data into 3ds Max from Houdini groups:

3ds Max Output

Group Name

Group Type

Description

Vertex Selection

hemax_vertex_selection

Point

This group controls whether the 3ds Max vertex of the generated geometry will be selected. When the point is a member of the group, the vertex will be selected in 3ds Max

Face Selection

hemax_face_selection

Primitive

This group controls whether the 3ds Max face of the generated geometry will be selected. When the primitive is a member of the group, the face will be selected in 3ds Max

Edge Selection

hemax_edge_selection

Point

This group controls which edges of the generated 3ds Max geometry will be selected. In order for an edge to be selected in 3ds Max, both points that comprise the edge must be a member of the group

Spline Inputs

This section describes the data that gets marshalled into a Houdini curve when a 3ds Max spline is provided as an input to an HDA.

3ds Max Input

Houdini Attribute

Attribute Type

Description

Material ID

hemax_matid

Point

This attribute stores the material ID of the 3ds Max spline segment that starts at the corresponding point

Spline Outputs

This section describes the data that gets marshalled into a 3ds Max spline from a polygonal curve output of an HDA.

Houdini Attribute

3ds Max Output

Attribute Type

Description

hemax_matid

Spline segment material IDs

Point

Sets the material ID of the 3ds Max spline segment that starts at the corresponding point

Curve Inputs

This section describes the data that gets marshalled into a Houdini curve when a 3ds Max curve is provided as an input to an HDA.

3ds Max Input

Houdini Attribute

Attribute Type

Description

Material ID

hemax_matid

Detail

This attribute stores the material ID of the 3ds Max curve

Curve Outputs

This section describes the data that gets marshalled into a 3ds Max curve from a NURBS curve output of an HDA.

Houdini Attribute

3ds Max Output

Attribute Type

Description

hemax_matid

Curve material ID

Detail

Sets the material ID of the 3ds Max curve

Houdini Engine for 3ds Max

Getting started

Using Houdini Engine

Reference