Grow

../_images/pgYeti_grow.png

The Grow node is used to create fibres ( fur/hair ) using input particle locations as the seed for each fibre. Yeti loops over each input particle and determines various potential attributes for each which may include length and direction. The new fibres will follow the final resolved direction ( which defaults to $N ) and will be made up of Segment Length long segments. Grooms and Guides can be used as a second input which are sampled for their length which is applied to the final potential length of a Fibre - this will only set the length of the fibre with a Comb or Guide node needed to set the shape/direction downstream.

Note

It is important to remember that this Segment Length is a world space value, so if a fibre has a potential length of 0.5 and the Segment Length is 0.1 then a fibre with 5 segments will be create. Alternatively if the segment length is 0.5 ( the default ) then a fibre with 1 segment will be created. The number of segments will affect how downstream nodes may affect the look of the fibre.

Note

VRay does not smoothly interpolate fur/hair strands like other renderers, it’s advisable to make sure that enough segments have been created in the Grow node to give the output a smooth appearance at rendertime.

Inputs

Input Description
0 Data Flow Particles
1 Strands Groom/Guide Curves used to control the length of the created fibres

Grow

Parameter Description
Direction specify the direction of the fibre, defaults to $N which is the surface normal.
Minimum/Maximum Length the shortest and longest possible lengths for the fibres.
Length Multiplier a means of increasing the overall length of the fibres.
Length Bias used to control if the bias between the number of shorter and longer fibres. 0 is evenly distributed, -1 means mostly short fibres and 1 is mostly long fibres.

Geometry

Parameter Description
Segment Creation Style By Count will let you specify the exact number of segments per fibre via the Segment Count parameter, By Length will use the Segment Length parameter for segment generation.
Segment Count The number of segments per fibre.
Segment Length as each fibre is generated it creates segments along the length of the geometry, the segment length can be used to control how much detail there is in the fibre - for most fur you want to end up with about 2-3 segments for visual quality and memory consumption. If you’ve generated fibres with a length of 2.0 that would mean a segment length of 0.5 should be sufficient.
Inherit Attributes defines a list of attributes, each separated by a space, that will be inherited from the geometry the fibres are growing from.

Example

Maya File: examples/yeti_blendExample.ma

Maya File: examples/yeti_combExample.ma