The more I’ve studied eyes, the more complex they seem to me. One thing I’ve noticed that people get wrong with eyes (as I also did) is the blend between the iris and the sclera. It’s either too blurred or too sharp, usually the latter. From studying references of eyes: up close the transition is really smooth, but as you get further away the transition feels sharper, of course. If the edge of the iris is sharp from up-close, then most likely from a normal distance the eyes feel cartoony and unrealistic.

Additionally, iris size is a common mistake I’ve seen – it really makes a huge difference to your character’s appearance and can tip the scales into the uncanny valley. Measure the proportion of the eye that is taken up by the iris in your reference images and replicate that in your texture maps. The more you observe and study the real world, the more it will reflect in the quality of your work.

Building the Skin

My methods for creating realistic skin has evolved over time, but one thing has stayed pretty constant and that is that I’ve always used Texturing XYZ’s scanned data maps. The most recent approach to creating skin uses their multi-channel pack where I carried out a channel-packing method. This involved adding a displacement, specular and haemoglobin map into the Red, Green and Blue channels of a file to produce a green, weird-looking map that would then be projected onto the model in Mari. This was then separated back out and applied accordingly. You can discover this workflow in-depth on the Texturing XYZ site.

Furthermore, shading skin in Arnold can be a tough feat, it involves painting additional texture maps such as subsurface weight, specular roughness, and even coat weight and roughness maps for representing the oilier zones of the face. Look-dev is a process that requires a lot of patience and experimentation. I like to adopt an efficient Photoshop-to-Maya workflow, whereby I can make a small change to a texture map in Photoshop, save it and refresh the Arnold renderer to see the updated results.