Find this section in the Attribute Editor for material nodes (Anisotropic, Blinn, Lambert, Phong, and Phong E). For information on how to set these attributes, see Set per-material vector rendering options.
When you turn this attribute on, you can render edges that would usually be obscured by the object. The edges are rendered as if they are masked by the transparency.
When you turn this attribute on, an outline appears along the point where two objects intersect. Use the Edge Priority setting to resolve edge outline conflicts (when depth does not automatically do so). This attribute is also located in the Render Settings, Maya Vector tab, in the Edge Options section.
The Edge Priority value determines which outline style is rendered at the intersection when the intersecting objects have different outline style settings, or when edges come very close to intersecting.
Typically, if objects are at differing depths, the edge priority makes no difference because the object that is closer to the camera supersedes, and its outline style is rendered. This setting is useful when the depth of the objects are the same, or very close. In this situation, the edge priority can determine which object’s outline style is rendered. The higher the value, the higher its priority.