The key to understanding 3D images lies in understanding the grey scale bump masks. ... The mask that created the one on the left was cereated by selecting the round, white area, and giving it a single gaussian blur of 16 pixels. The one on the right was created using multiple gaussian blurs, first 8 pixels, then 4, and then 2. ... This is due to the extreme amount we've distorted the image, remember, that grey mask only has 256 levels. ... The gradient tool will always create a sharp angled mask. ...