Best way to track an Obj or Texture along topology?

[sami]

hey I know I've seen tuts for "the ball rolling along mountainous terrain" etc . But what's the best way to track an object along the topology of another object?

Basically I have an quite odd shaped eyeball (well not me personally :p ) and I'd like to move a null which drags the pupil object around the exact topology of the other object (which is not spherical). Essentially magnetizing the pupil object to the surface of the eyeball. It would be a bonus if it also deformed the pupil object (say assuming it was a disc) to the eyeball object when it went over concave or convex areas of the eyeball object.

Is there any 3rd party plugin or technique that could be used for this sort of action? I have a few things that work but I would like a fresh set of opinions too :D

thanks...

/sami

[prospector]

I find that tracking works good along strange shapes works really good this way...

From the object in question, highlight and copy to a new layer, the points in object where you want something to follow.

then in the new layer highlight the points in the direction of travel,
make it into a spline

sometimes if there is little geometry to work with the ya might have to add a few points to get it to follow exactly how ya want, by using original object as bkgrnd.

make that into a motion and save the motion file.

In layout have the secondary object use the motion path.

will let you make ants or bugs follow around fingers,up the arm while it circles and into ear, where it slowly digests the brain into a mass of quivering jelly....

oops
went off on a tangent;)

[sami]

thanks prospector - I appreciate your tip - thats the way I would normally do it if it was supposed to track along a fixed path.

However in my example - say for the weird shaped eyeball - I would want to dynamically move a null ANYWHERE and have it track the pupil on the surface of the eyeball - otherwise doing it the way you described would mean the character could only look in particular directions.. Am I making sense? :confused: Sorry if I'm not being clear - I can up a picture if that would help.

thx
sami

[WCameron]

All I can think of off hand is make the Pupil a texture map,
and move it with a null.

the tire tutorial, btw, is in _features/Texturemotion.
I dont have Lightwave in front of me atm so I cant open it up and check to see how its set up. it might be adaptable to what you want though.


- Will.

[meshmaster]

If Caligari's trueSpace can have a magnet and a "look ahead" thing for movement, surely Newtek could build something like that into Lightwave!!! :)

[prospector]

Ok so the eye has to move?
and the 'pupil' moves?

then yes use the texture nap moved by a null and put some FX on the null so it either pushes in the eye or bulges it out (like they do the cow in the manual)
as you move the texture the vally or bump will also follow.

If I get ya right

never tried but I don't think ya can parent a mkotion file to an object...... yet.

[WCameron]

Hyper subdevide the Eye object, tie both a "Pupil" Image map and a Deformation map to a Nul, then move the null and a raised,
colored pupil will slide across the surface of the object.

I ronically I just set up a sample object/image and scene for you and it freakin crashed....


- Will.