View Full Version : Aim Constrain Probs On An IKSpline Chain

04 April 2007, 03:09 PM
hi people, Im having a rather anoying problem with an aim constraint on 2 locators! The basic idea is one locator is used to affect the rotation of the other locator by using an aim constraint and then the rotation is then plummed into the Roll attr on the ikspline handle. It works perfectly on 3 of the 4 grid regions except the positive X and Z region where the locator which is rotating pumps out incorrect rotational values. Im not sure if it is a gimble lock or whether my settings are incorrect on the aim but i think it is set up correctly! If anyone could shed some light it would be greatly appreciated as I need to solve this very quickly for a group project as deadlines are close! Thanks in advance!!!

Here is a illustration of what is happening, as you can see the Y axis is pointing towards the R near the back of the head but when it reached the red region it flips out!

Here is the actual rig

Joe Hughes
04 April 2007, 03:48 PM
huh, thats a good one. are you using the defaults for the aim constraint? make sure it is pointing in the correct direction. if you are using defaults then your world up is set to vector, i would create another locator, call it up or whatever you wish and us that as your world up object by placing the up vector the direction you want the aim to use as reference for up and set the world up type to object up and in the world up object box type the name of the object which in my example was a locator named up so in that box you would type up and add your aim const. like that.

thats the best i got, hope it helps.

04 April 2007, 08:58 PM
Cheers m8 i will give it a try and see what happens :)

04 April 2007, 11:06 PM
ah it still doesnt work :'( man this is really annoying me lol, iv read mayas help and iv tried lots of different settings and tried it just using nulls and locators instead of attaching it to the rig and it still does the same thing... mmmm :shrug:

04 April 2007, 04:00 PM
ah well iv now decided to just add the Roll to an attr in the controls so the animators will just have to key it when they rotate her... which isnt very convenient but its the only solution i can come up with :rolleyes:

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04 April 2007, 04:00 PM
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