eyeball focus point locator


#1

is there a way i can set it up so both eueballs are pointed at a locator, so when i move it both eyeballs center on the point? eyes are never parallel, and it would be nice if there was a way i didn’t have to guess where they’re looking. basically i want to have the rotation of the eyeball somehow affected by the position of a locator, without having the eyeballs translate.


#2

Aim constraint.

Under the animation context, it’s in the Constrain Menu. Create your locator, select it, select your eyeball, and aim constrain it. Now, when you move your constraint, the eye will follow.

If it constrains the wrong pole, just adjust the aim vector settings in attribute editor.

Ricky


#3

muchas gracias, amigo


#4

Just want to add to this, I find CG eyes are often a classic example of the old adage that ‘just because it’s physically right, doesn’t mean it looks right’. I don’t know why but I’ve had models I’ve set up to be focusing at the correct object and distance, yet from some angles they still look they’re either cross-eyed or staring wistfully into the distance.

To fix this I use a setup where each eye is aim constrained to it’s own locator, and the two locators (which are the same distance apart as the eyes) are grouped. The group node is then aim constrained back to the midpoint of the eyes. So when you move the group around, the eyes follow the locators and the locators always face the head. There’s also a custom attribute with a couple of expressions for controlling how far apart the locators are. It allows for finer adjustments to stop them looking cross eyed or googly eyed like the late great Marty Feldman :slight_smile:

Anyway here’s a simple version of it if anyone wants a look (aha, bad pun intended). Select the Aim Group and move it about to rotate the eyes, and change the Eye Separation attribute in the channel box or AE to alter the distance between the locators.

Hope somebody finds it useful.

Wabo.


#5

Waboflex gives a good description for how to set up eyes. :slight_smile: There are a couple of other things to consider in addition to his description. For cartoon characters you may want the individual eyes that are parented under that EyeTarget null to be freely moveable. This gives you individual control over where an eye points if you need it, so you can make one eye spin clockwise and the other counter-clockwise when the character is dizzy. Also, you will want to set the up vector on the aim constraint to ObjectUp, and then set the up object to nulls which are directly above the eye bones/nulls, and parented to the head. This keeps the eyes oriented correctly when the character leans his head to the side… otherwise the eyes will spin in their sockets.

Later,
Michael Duffy
mduffy@ionet.net


#6

I’m personally not a big fan of aim constraints as although, mathematically, they may resolve to point an XYZ pole at the target, that may actually speak very little to how much of the surface of a sphere is exposed through the eyelid, and therefore throw the perception of where the eye is looking way, way off. It’s oftentimes better to set orient constraints for the eyes instead, and give the locators (or nulls, or whatever) a common parent, that way their relationships stay relative to not only eachother, but they stay relatvie to what -looks- right, as you’ll animate it, as opposed to what -is- right, which, as I’ve just hopefully made a good case for, just doesn’t matter.

Also, remember that if your upper eyelids don’t follow the height of your pupil/iris that the direction in which your eyes are looking can be skewed visually, not to mention, that the emotional perception can change drastically. (Eyes up, no lid movement looks like your character got sleepy, eyes down, no lid movement looks like they’re excited).

I’ve got a book out there on this jazz if you’re interested, it’s actually all about faces, modeling, rigging, animating, and most importantly -understanding- so that you can control the messages your face puts out instead of taking random shots at things that SEEM like they might work. Anyways, hope that helps -J.

Booky book book


#7

what a shameless plug…:surprised

heh heh, just bustin your balls. your book rocks. i got my copy last week, and i’ve been reading every day since. your technique is very interesting and very usefull. i normally hate cg books, but yours is bearable and relevant to production. really good stuff! :beer:


#8

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