def METHOD_NAME(self, obj, job):
    """opSetDefaultValues(obj) ... set depths for engraving"""
    if PathOp.FeatureDepths & self.opFeatures(obj):
        if job and len(job.Model.Group) > 0:
            bb = job.Proxy.modelBoundBox(job)
            obj.OpStartDepth = bb.ZMax
            obj.OpFinalDepth = bb.ZMax - max(obj.StepDown.Value, 0.1)
        else:
            obj.OpFinalDepth = -0.1