Aim eyes without them revolving?
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I'm having an issue with Constraint/Aim on a character's eyes, that in the process of aiming, the eyes rotate rather than just go up and down and side-to-side when their head moves around. Is there a way to constrain the eyes so they stay "upright" in the head without revolving around?
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Hi Tanim8r,
The first step would be to explore why it happens before adding more items to address it.
The simplest way is typically to use an UpVector in the setup. Move the Target to see if it is stable for your needs.
CV4_2026_drs_25_ANet_01.c4dA reason I suggest exploring why it happens is that an UpVector has influence, and if that influence is not really needed, it would perhaps limit options, or, if used wisely, increase them, if needed.
All the best
Please have a look to this small example:
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Hi, thanks for the file. Unfortunately, an UpVector would keep the eyes still vertical when the character tilted their head to side, for instance (as shown in this image). I need the eyes to maintain a "local vertical" to the character's head, while moving side to side and up and down at a target.
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I think you put me onto the right track with your mention of UpVectors: I used an Animation/Target tag to point the eyes at a target, then put an Empty Polygon object parented to the character's head directly above each eye and told the Target tag that each of the Empty Polygons would be UpVector object. Seems to be working. Thanks!
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Hi Tanim8r,
The file above is set up to keep the eyes with the head motion. I animated here the Head Null, important here, the"target'Upvector Nulls are in the Head hierarchy. The Face Capture camera shows that they sit pretty stable. Whereby a Face Camera is rarely used in animation for the final images, meaning the audience doesn't see it.
CV4_2026_drs_25_ANet_02.c4dIf that is not the majority of cases, then look at the second setup, where the Up-vector stays in the head rig but the Eye Target is stable.
CV4_2026_drs_25_ANet_03.c4dIf both are needed equally, a Mix Node in XPresso can be used to switch between two targets. Let me know if that is needed.
All the best
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Ah, okay, I understand your setup and why it didn't work for me. I use the eye target differently in that I have the eyes of a character lock onto a point in space not parented to the character's head rather than have the target travel with the head, so when I tested your file, I moved the target outside the head like I normally do, so that was the problem. I prefer to have the target as a point in space not parented to the head since then the character's eyes follow that point in space when they make subtle movements without me having to manually adjust for that. Is there a solution to "lock" the rotation relative to the head rather than to the world but still get the sided-to-side and up-and-down rotations? The solution I came up with seems to work okay, but I feel like there must be an easier way.
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Hi Tanim8r,
Yes, the easiest way for the Animator is the key. The typical production rig is set up so that the animator is not focused on the rig setup tech. Meaning, as little as possible, but as much as needed, and as easy as possible to use.
If you need both options, then below is the next step. It has, as mentioned earlier, a Mix slider included. With that, both targets can be in the scene, and even smoothly blended between the two.
The next step would be another option to reset the Head-based target to the Object Target (which needs to be in the limits of the Eye movement, of course. In short, it is like the IK to FK sync option in most advanced rigs.
Anyway, that adds another step, and perhaps dragging the Head target toward the Object Target will result in similar effort, but will work more naturally (IMHO). Anyway, a rig is based on the Artist's needs and not how much a Technical Director can add to it.How much can be edited can be explored with the Character Objects. Especially when you make them editable, to see how they should be used or set up for production. Enjoy the exploration.
Have a great weekend.
