Create Extrusion Along Strands

Replaces the "self" Topology with an extrusion based on the strands of a point cloud. The number of segments in the extrusion is the same as the number of segments in the strand. The size of the cross-section is modulated by the particles' StrandSize attribute. See Creating an Extrusion Along Strands.

NoteAll strands must have the same number of segments, that is, the size of the StrandPosition array must be the same for all particles. Among other things, this means that this compound is not compatible with strands created by Generate Strand Trails.

Tasks: Topology/Generators

Output Ports: Execute

Point Cloud

Cloud Name	Connect the name of the point cloud, or a prefix to use with Reference.
Reference	Specify the point cloud. If anything is connected to In Name, it gets prefixed to the name specified here.

Base Up Vector

UpVector Mode	Controls the orientation of the cross-section: From Emit Location calculates the orientation from the particles' EmitLocation. If that attribute is undefined, it falls back to From Particle Orientation. From Particle Orientation uses the particles' Orientation. If that attribute is undefined, it falls back to From Strand First Tangent. From Strand First Tangent calculates the orientation from the first segment in each strand. From Custom Vector uses the UpVector specified below.
UpVector	The vector to use when UpVector Mode is set to From Custom Vector.
Rotate Normal	Twists the cross-section along the length of the strand.
Rotation Angle	The amount of rotation along the length of the strand.

Base Shape

Controls the shape of the cross-section.

Nb Positions	The number of subdivisions when Base Shape Type is "Circle".
Base Size	The size when Base Shape Type is "Circle". Note that the size of the cross-section is further modulated by the particles' StrandSize attribute.
Base Shape Type	The shape of the cross-section: Circle Custom uses the polygon mesh connected into Custom Shape Name.
Custom Shape Name	The shape to use when Base Shape Type is "Custom".

Cap Options

Closes the Start and End of the extrusion.

Per Extrusion ID

Specify an attribute name to store an integer that you can use to differentiate the vertices extruded along different strands.

Automatic UVs

Enable Auto UVs

Creates an attribute based on the extrusion that you can use as texture UV coordinates.

Reference

Specify the name of the attribute to use.

U/V Start/End

Use these controls to limit the texture coordinates of the caps to a specific section of UV space. This has the effect of scaling the texture on the caps.

To control the projection along the extrusion, use the Repeat controls on the Advanced tab of the Image shader in the render tree.

Advanced

Mute Deformation

Creates the geometry and other attributes but does not deform it along the strand. This allows you to create the geometry in one tree, and deform it along the strand in another tree higher up in the construction stack using Deform Strand Extrusion.

When this option is on, the Base Up Vector settings in this compound have no effect. Use the equivalent settings in Deform Strand Extrusion.

Remove Strand Position

Ignores the specified elements in the StrandPosition array. This is useful when using strand compounds that set StrandPosition[0] to the particles' PointPosition.

If Mute Deformation is on, this option should be set to the same value here and in Deform Strand Extrusion.

Index

The index in the Strand Position array to ignore.

If Mute Deformation is on, this option should be set to the same value here and in Deform Strand Extrusion.