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Paul Forwood

Surface constraints are driving me crazy!!!

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I have wasted a whole day trying to get my head around surface constraints!

 

The task is a simple enough one:

 

Constrain pupils to an irregular eyeball and drive them with pose sliders or an eye target.

 

I can get it to work just fine as a stand-alone eye model using pose sliders but within my model the constrained pupil bone always flips 180 degrees. No matter what I try it just won't work! It's like there is some kind of alien intelligence at work!!! :(

 

All the bones involved, (pupil-bone, surface-bone and pointer-bone), are on the same level of the hierarchy, parented to the head-bone.

 

If I use a dome for the pupil the domed side will always flip so that it is facing the eye instead of facing out. If I rotate the pupil's bone in the model it still flips the pupil in an action or choreography. I thought it might have something to do with the fact that I was using a hemisphere with no back geometry so I tried using a sphere instead but it still flips. I have tried moving bones around to various locations, adjusting offsets, you name it, I just can't understand why this simple task is fighting me!

 

The documentation for suface constraints is scant, to say the least, and I haven't been able to find anything more than what is in the Tech reference.

 

I just want to understand what is happening and get over it. It is driving me CRAZY!!! :blink:

It is not a problrm with A:M, as far as I can tell, because I have tried this in versions 11.1i, 12t and 13 alpha 9 with pretty much the same results.

 

Someone out there must have a handle on this so, PLEASE, save my sanity!

 

Ta very much! :)

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Paul,

 

Here is a model I dug up off my hard drive that has all the elements you are using. It works fine by itself. (In fact, it may even be the model you started with) All I can suggest is that you compare settings here versus your model. Also, you could make this model a child of your head bone but not part of your geometry and see if that makes a difference. The only other thing I can think of would be to look at roll handles and store roll options.

 

Scott

Cartoon_Eye.zip

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Paul, I had to stop reading.

Becuase I've been there, trying to do the eyeball thing just as you were doing....

This was a long time ago.... galaxy far far away... that whole thing.

 

All I can say is that you should use the KeeKat method for this.

I use it on my super hero character and it it works like a charm.

 

Basically model the eyes as pefect spheres. duplicate and shrink. MOve to surface make black or whatever

this is the pupil.

Add 2 bones.... one for the eyeball, one for the pupil with the origin in the same spot.

Now, make action to scale the eyeball bone. the pupil will scale with and move along the surface.

 

I also make the eyelids like this. It can't be beat.

 

If you say that the design of the character will be affected to do this.... so what, redesign and do it cause its functionality makes it worth it.

 

Mike Fitz

www.3dartz.com

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Here is a model I dug up off my hard drive that has all the elements you are using. It works fine by itself.

 

Thanks, Scott!

 

That's interesting. That is much the same as the model that I have made, with the same bones and arrangement. I started from scratch though. The main differences that I can see are that the pupils in my model are constrained to the surface in a pose while in your model the constraints are applied in an action. I wanted to have control over them via pose sliders. I am using a decal to define the iris and pupil on the small hemisphere rather than just having a black dot so I must be able to control the direction it faces.

 

In a stand-alone model, like this, I have been able to get them to work with pose sliders but for some bizzare reason I get that flipping pupil when I try the same setup on my character's eyes.

 

If you say that the design of the character will be affected to do this.... so what, redesign and do it cause its functionality makes it worth it.

 

Well, that is one way that you can approach the problem. Okay if you are building a free-form character but if you are intending to reproduce a character design that requires a specific look you can't compromise in that way. Thanks, Mike, I will take a look at KeeCat and see how it's handled there.

 

Thanks guys! A little moral support goes a long way! :D

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Silly idea, but just a thing to do... check your normals on the half sphere for your eyeball... make sure they point outward correctly.

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check your normals on the half sphere for your eyeball

 

Thanks, Jody, but that is one of the many things that I checked many times. All normals are facing out. :blink:

 

Here is a rough example of the iris/pupil working on a stand-alone model:

( Sorry, I didn't get around to compressing this as it was just a quick test render, destined for the bin. )

 

[attachmentid=15043]

 

I understand that the rise and fall of the pupil/iris is caused by the changing density of the geometry that it is passing over. That can be fixed but what could be causing it to flip when I try this on my character's eyes?

 

:(

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Paul after seeing your animation, and if all your characters eyes will be in that fashion....

there is no reason why you wouldnt use the keekat method, at least any reason that I could think of.

 

Just my opinion....

 

Mike Fitz

www.3dartz.com

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check your normals on the half sphere for your eyeball

 

Thanks, Jody, but that is one of the many things that I checked many times. All normals are facing out. :blink:

 

Here is a rough example of the iris/pupil working on a stand-alone model:

( Sorry, I didn't get around to compressing this as it was just a quick test render, destined for the bin. )

 

[attachmentid=15043]

 

I understand that the rise and fall of the pupil/iris is caused by the changing density of the geometry that it is passing over. That can be fixed but what could be causing it to flip when I try this on my character's eyes?

 

:(

 

I was dogged by this same thing a while back with 8.5. I think, I can't quite remember, that I ended up manually rolling the pupil bone in the first frame of the choreography, kinda making an offset, and then things worked. It was weird. Although, I know I didn't use a pose slider for movement. So this solution may not work for you.

 

Cory

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I don't know exactly what I did... but I got it working!

 

I deleted the surface constraints pose and rebuilt them in a new pose. Then I noticed that offsets were working again so I spun the iris/pupils around to their correct position and tested the pose sliders in an action. No joy.

 

I then deleted a flattening pose and several earlier versions of the model from the project. Saved, reopened and...Bobs your uncle! :-)

 

Thanks to everyone who offered suggestions! :-D

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Nothing so satisfying than getting something to work, even if you don't know why!

 

Glad we couldn't be of any help! :)

 

Scott

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