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When this attribute is checked and the attached object is a polygon mesh, any color sets it contains that defines per-vertex color will be exported to rendering. Each color set will be exported as a color array bearing the same name as the color set. Additionally, a float array is also exported; its name consists of the color set name with ‘ alpha’ appended to it. It contains ‘0’s for vertices where the color set is not defined, and ‘1’s were it is defined. This attribute is off by default. See Section 5.4.3 [Exporting Per-Vertex Attributes on Polygon Meshes], page 131 for an example on how to use this.
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