Part 3 Eye Can See You

Before you can begin making area around the eyes it helps to have the eyeball already in place. Today we're going to make a short deviation from Polygons and switch over to Surfaces.

Detailed instructions below the video.

Details

• Create a NURBS Primitive Sphere. If your sphere is displayed with straight edges then press 3.
• Rotate your sphere 90 degrees in the X direction so that the pole faces forward and center it over the middle of the front image plane's eye.
• Scale down the sphere. You may have to guess a bit here, since most of the eyeball tends to be covered by skin muscle and bone, but it should be a little larger than the eyelids. Now you can match up the front of the eyeball with the side image plane.
• Of course, the front of your eye isn't the front we've got here. A real eye has a little dome on the front called the cornea. Right click the sphere and select Isoparm.
• Click on one of the horizontal curves and drag it forward. This should mark the side of the iris.
• Then go to Edit Nurbs: Insert Isoparms.
• Repeat those steps several times in order to increase the geometry in that region.
• Select the CVs controlling the front of your eye and begin scaling and moving them to create a dome.
• Freeze transformations and delete history. I know I say to do this a lot, maybe even more than you need to, but I've seen history build up to the point where it slows down the computer.
• Now we return to Polygons to begin the iris. The iris is roughly toroidal in shape and located just behind the transparent cornea.
• Create a torus and reduce the geometry. You can smooth it later, but for now we don't want too much to work with.
• Scale it down along Y to flatten it out, rotate it 90 degrees on X, alight in with your front image plane, and scale it down to fit.
• Select the inner ring or two and scale them to match your pupil.
• Jumping back and forth between front and side views, begin moving and scaling rings of vertices to make the iris bow inward.
• Delete history and freeze transformation.
• While we're at it, let's take care of the UV layout as well with Create UVs: Planar Mapping option box. Project from Z Axis. Scale this down in the UV Editor. Delete history again.
• Make a new Lambert, call it Iris.
• I arbitrarily colored it brown, but I intend to replace that later with close up photo of an iris.
• Assign Iris to the torus.
• Name the torus LIris, since this is the Left Iris. For the same reason, let's name the sphere LEyeball.
• Create a new blinn and change the color to an off white.
• Assign it to LEyeball and name the blinn Eyeball.
• Although the pupil is just a hole in the eye in real life, we don't want to risk seeing the back of your sphere when we look through it, so we'll place a black object there to simulate it. It doesn't have to be much. Create a polygon sphere and reduce the geometry.
• Delete the top of the sphere.
• Scale it down and stretch it along its Y Axis.
• Rotate it 90 degrees on X and place it right behind the hole in the iris.
• Freeze transformations and delete history.
• Create a new lambert, change it to black, name it Pupil, and assign it to the dome.
• Name the dome LPupil.
• So you've got an iris and a pupil set up inside your eyeball, but what good is it going to do you if you can't see them? We need to make the cornea transparent but leave the rest of the eyeball opaque. Go back to your Hypershade and select Eyeball.
• Add a ramp to the transparency. The ramp only needs two colors, white and black. Change the type to a U Ramp so it faces the right direction. The white is transparent and you'll want it centered over the cornea but it's hard to do that if you can't see where it is.
• Return to the blinn controls and scroll down to find the Hardware Texturing tab. Open it up and click the Textured Chanel. If it doesn't give you any options then you'll have to save and restart Maya. That's an annoying glitch you'll have to get used to dealing with.
• Once you've got that sorted out, select Transparency from the drop down list. You eyeball will now display the transparency ramp instead of the colors.
• Now you can adjust the placement of the transparent region by moving the black and white controls in the ramp. ou'll want to check it out with a few test renders to make sure the cornea blends in to the rest of the eyeball while still covering the edge of the iris.
• The eyeball is wet and shiny, so it has a small, bright specular highlight. To get this effect with a blinn shader you have to reduce the eccentricity and increase both the specular roll off and the specular color.
• Around this point in the video, I realized that the pupil was still a bit too big, so I had to scale it down a bit more.
• When you look at an eye from a nearly side view, the iris appears to bulge out into the cornea. This is due to refraction. We don't have that yet. Go to your Render Settings and make sure Raytracing is checked.
• Under Eyeball's Raytrace Options, check Refractions.
• The index of refraction is a ratio between how fast light travels in a vacuum compared to how fast it moves in a given material. This difference in speeds determines how much it is bent from its original direction. According to this table, the cornea's Refractive Index is 1.38, so that's the value we input. You can always adjust it after some test renders if it doesn't quite work as expected.
• Turning on Raytracing also allows Reflectivity, which I don't want at the moment. I'll turn that off for now, since it's just a distraction. I can always bring it back later, but to a lesser extent.
• There's one more thing this ramp is good for. Select the ramp node in your Hypershade and shift select the eyeball.
• Click Edit: Convert to File Texture Option Box. Here you can save a tiff of the ramp in your images folder. You can use this to see where to put the veins when you're creating the eye's color map in Photoshop. You'll want them to fade out before you reach the cornea, unless you want some seriously bloodshot eyes. I won't go into the details of creating color maps here. I'd rather focus on modeling for the time being.
• This created new shaders which you don't really need. Reassign Eyeball to LEyeball.
• Select all three parts of the eye, freeze transformations, delete history, and group them.
• Modify: Center Pivot.
• Name this group LEye.