Gabriela Salmeron 

Guide Curves

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Guide Curves are normal Maya curves used to guide fibers or instances in Yeti. Its main utility is to be able to connect them to a Rig and animate the fibers or instances easily and efficiently.
To use them in a Yeti graph, you first need to create Guide Sets, which are groups of Guides that will be brought to the graph through the Import node. To create them, select all the guides you want to put in the group and go to Create-> Set-> Set. Then go to the Graph-> Input Guide Set tab of the top node of Yeti and add all the sets you've created. To add or remove curves to a Guide Set, you can use the Relationship Editor in Windows-> Relationship Editors-> Sets.

 

Important: The pivot of each curve must always be in the [0,0,0], being only possible to move its points in Edit Mode (F8). If the pivot is out, there will be an accumulation of this translation and incorrect positioning of the fibers and instances (Double Transformation). To place a pivot in [0,0,0], we can use the Freeze Transformations command followed by Reset Transformations, in the Modify tab. It is also important that the first control point of each curve is close to the mesh, not infiltrating it nor too far from its surface. We can use the Snap function to position the first point of the curve close to the mesh. If this distance is not adequate, instances or fibers may lose their reference and behave incorrectly. Finally, if the feathers are being instantiated inverted, you must invert the direction of the curve in Curves-> Reverse Direction or even rebuild them in Curves-> Rebuild.

Guides Sets are imported into the graph and can be used on the Scatter node to control density, on the Grow node to control the fiber size and with the Guide node that will work as a Comb and Clumping together.
When we add a Guide Set on the top node of the Yeti, extra attributes are released on each curve to control the wire parameters. These parameters are like the attributes of a Groom, but already automatically connected to their functions.
We define your area of ​​influence with the Inner and Outer Radius. The Inner Radius will be the area where the curve parameters will act with 100% effect. The Outer Radius stipulates how far the effect of these parameters will be decayed, and outside it will have 0% effect.