Awesome, thank you!! This allows to cast shadow without render to the main pass or viceversa. It is possible to change the position of the shadow also, but Is there a way to change the shadow depth per pixel?
PD: Is it possible to acces other passes with instructions via custom node?
PD2: Can I acces the cubemap in the shader without modify the engine?
EDIT: This can be used to achive a primitive slope bias, that actually correct the problems mentioned in the thread with the out of the box UE4. Im having a little trouble to get the it working on point lights tho.