new layer name
new layer color in js object format: {r:number, g:number, b:number)} where number is from 0 - 255
If layer_name is valid, the layer's index (>=0) is returned. Otherwise, RhinoMath.UnsetIntIndex is returned.
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The index to search for.
A Layer object, or null if none was found.
The name of the Layer to be searched.
The id of the parent Layer to be searched.
A Layer, or null on error.
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