Simple strands are rendered using Arnold's curves primitive.

The following attributes are used, if available:

  • StrandPosition. 
  • Size / StrandSize for constant / varying thickness.
  • Orientation / StrandOrientation for constant / varying orientation.

If instead, the strand has some instance shape connected, then the shape is always bent along the strand, and a single polymesh object (or group if the instance shape is a model) is created for each strand.

You can instantiate meshes and models.
The per-point attributes (like the color in the case below) are exported as constant data for each instanced object.
The per-strand-point attributes are exported as varying data (one value per curves point) only for plain curves nodes.


The strand orientation attribute, if available, is used:

  • In the case of a shape, to twirl the shape around the strand.
  • In the case of a plain curves node, to set the orientation of the curve. To do so, apply an Arnold Parameters property to the point cloud, and set the Curves Mode to Oriented Ribbon (ICE Strands).

More information can be found here: Hair / curve parametersHair Tutorial.


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