Soft contact shadows

Does anyone have any insight as to how to achieve soft contact shadows? Please see screenshot. Its not really an ambient occlusion pass, its like a very blurry shadow projection from straight down. On a high level I’m thinking render the model once from the top, invert the alpha, blur it , then apply the render texture to a plane aligned with the bottom of the model. That said, im not sure exactly how to go about implementing this. I don’t need source (that would be nice however), I just want to know about possible approaches and techniques. Thanks.

That’s hard to tell on the picture. Maybe it’s an ambient occlusion pass but that would be exaggerated in some ways…