Version: 2017.1
public int ignoreLayers ;

Description

Which object layers are ignored by the projector.

See layer mask.

By default this is zero - i.e. no layers are ignored. Each set bit in ignoreLayers will make this layer not affected by the projector.

    function Start() {
        var proj : Projector = GetComponent (Projector);
        // Make the projector ignore Default (0) layer
        proj.ignoreLayers = (1<<0);
    }