Houdini 16.5 Nodes VOP nodes

Bind VOP node

Represents an attribute bound to VEX.

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The Bind node represents the binding of the input geometry to the vex function. For example, if you bind force you can pick up the attribute called force from your input geometry.

Note

If you wish to make a variable mapping, adjust the default value, or change the type info, use the Add Attribute VOP.

Parameters

Name

The name of the new parameter, both in the VEX function declaration, the definition of any OP type that uses the VOPNET, and the VOP tile’s output. If a parameter by this name already exists, this operator will reference it and will disable most of of its own fields, such as the Parameter Type and Parameter Label.

The name must not be a reserved keyword.

Type

Specifies the VEX data type of the new parameter. It can also specify how the parameter should be represented in an OP dialog. For example, a VEX vector can be viewed as 3 float values or as a color value.

Override Type with Input

If the input is wired up, it is used to determine the type rather than the type menu.

Default Values

Depending on the parameter type selected, it represents the default value of the parameter in the VEX function and in the OP type that uses this VOP network.

Use This Node to Set Parameter Attributes

When several Parameter and Bind VOPs have the same Parameter Name, only one of the nodes is used to control the attributes of the parameter. Houdini decides which node to use for this by searching all the nodes according to the user defined order, then traversing inside subnets. If none of them have this parameter turned on, the first one found is used to set the parameter attributes. If one or more do have this option turned on, the first one with this option is used, even if another node (with this option turned off) is found first.

Use Own Export Context

When several Parameter or Bind VOPs have the same Parameter Name, some other node will determine export context. However, it may be desirable to have each Parameter VOP exporting in a different context. In such cases, setting this parameter will enable this node to specify own export context, independent of the primary definer node.

Use Input Value If Parameter Not Bound

If true, the VEX function parameter is checked to see if it is bound to an attribute in the current VEX context (e.g. point color). If not bound, the input value is is assigned to the VEX parameter. In a Surface VOP context, a VEX parameter is bound if the geometry being shaded has an attribute with the VEX parameter name.

Export

Specifies whether the new attribute can be exported to other contexts (written to as well as read from). If set to Always or When Input is Connected, this operator gets an input. The value wired into this input is then assigned to the exported parameter. In a Surface network, exported parameters can be used to create deep rasters. In SOP networks, the exported parameters create new geometry attributes.

Never

The binding will not be exported.

Always

The binding will be exported.

When Input is Connected

The binding will only be exported if the node’s input is ultimately connected to another VOP.

Export in Context

The context or contexts that the parameter is exported to. Use whitespace characters as separators when specifying multiple contexts.

Inputs

Unbound or Export Value

The value assigned to the new parameter if the Export Parameter toggle is checked or if the parameter is not bound when Use Input Value If Parameter Not Bound is checked.

Outputs

Parameter

The value of this VEX function parameter.

Is Parameter Bound

True is the new parameter is bound to an attribute.

Examples

The following examples include this node.

PathAnalysis Example for Find Shortest Path geometry node

This is an advanced example of how to use the FindShortestPath SOP to prefer "central" paths, based on centraily measures computed using FindShortestPath and AttribWrangle. This helps avoid staying too close to walls where avoidable.

Turn on the Display Option > Optimization > Culling > Remove Backfaces to see inside the space more easily. Try visualizing the different centrality measures using the switch node. The same example without considering the centrality of the path is demonstrated in a side branch of the SOP network, in order to see the difference.

Clumping Example for Fur geometry node

The Fur SOP is used to instance hair-like curves.

In this case, the Fur SOP is used to create curves that can be used for clumping. A second Fur SOP is used to illustrate how to create hairs that use the clumping geometry.

WornMetal Example for Curvature VOP node

This example shows how the curvature vop can be added to a shader network to add a worn or distressed look to your material.

Fuzzy Logic Obstacle Avoidance Example Example for Fuzzy Defuzz VOP node

This example shows agent obstacle avoidance and path following implemented using a fuzzy logic controller.

See also

VOP nodes