Variance shadow mapping, well actually it's shadow volumes here. This technique is more plausible qua look like the picture you posted proves but the disadvantage for shadow volumes is that performance problems occur when adding shadow volumes to very high tesselated models. Tesselation is what you need here with shadow volumes since you need to accurately calcutate the object's silhouette. The images looks good so far but I wonder which technique you used to set it up via shader, just curious

Cheers

Frazzle