View Full Version : Animation trouble with IK and expressions

03 March 2005, 09:12 PM
I am remaking a little BBC2 animation (don't know who of you have seen this, but...).
Here's a link :

It's the remote one.

Reason for doing this...happened to catch it on Beeb2 and thought it may be possible in Lightwave (using expressions. as i haven't before) to animate the remote and thus move the Logo.

I have now modelled it, and my first problem in the rigging is the arms. They have two sets of 3 part hydraulics (i think they're hydraulics).
I was wondering the best way to rig it so that I can move the end piece "in and out" and it will first move all the way into the second then all the way into the first (and vice versa).

I hope I have explained this well enough.

Oh, and here is a pic of my model, which I have done quickly and the best I could from the one ref pic I had.

Any help or information would be greatly appreciated.

Cheers guys.

03 March 2005, 12:58 AM
cool animation Tho i would model a different character and do your own version of it
it's a cool idea and you could do alot with it :)

OK the arm thing:thumbsup:

setup the IK using the shoulder, elbow and hand objects then for the middle areas just bring pipes in for the upper arm and parented one to the shoulder and target it to the elbow and have the other parented to the elbow and target to the shoulder uses null as targets and parent the null to the joint to get the prefect position to the main joint

this will work for the low arm too very simple setup but will work fine

when setting up IK you don't have to conected mesh, IK only works from Object pivot points :buttrock:

03 March 2005, 07:58 PM
Thank you very much. I do appreciate your advice; however, I can't seem to implement anything.

I have since copied the left arm and broken it down into Shoulder, Two UpperArm "tubes", an Elbow, Three LowerArm "tubes", and a Hand.
I have also added a Null at the exact pivot point of the shoulder and one for the elbow; none for anything else yet.

In trying to implement what you had suggested, my first problem occurred when trying to target the first upperarm piece to the elbow (once it was parented to the shoulder), but it would rotate perpendicular to itself to face along Z-axis. So I re arranged the model and adjusted all the pivots again in Modeler so that the arm faced down the Z axis. Not sure whether this would mke any difference.

It now doesn't rotate, but I cannot seem to rig it to save my life.
This is the first piece of rigging I have ever done and the only tutorials I have read and watched have been for bone IK, etc in organic models...:( I'm stumped.

I have uploaded the model of the single arm if anyone would like to poke around with it. The scene file has the tow nulls but I have rmeoved all attempts at parenting, etc. I'm probably just being eally stupid (in modelling or rigging) but I have no experience thus far and am very lost.

Sorry for the uber long post. Any help would be brilliant. Thanks guys!

- Mike

03 March 2005, 08:08 PM
I have deleeted half the arm and uploaded the file now...contains the model and a scene where i have added a shoulder and elbow null.


If anyone can help or advise on the simpler things that I may not have read or understood that would be class! I'm still researching, but so far no luck...


03 March 2005, 12:28 PM
Sorry to be a bore; i suppose the basic idea is to have a 'telescope like' object and be able to animate the opening and closing by controlling the movement of one piece...

Any ideas, i assume it is a fairly simple IK rig?

03 March 2005, 06:28 PM
Your zip file cannot extract.. Might be corrupt.

I am going to guess you are struggling with gimble-lock. Check out the Twistable Spine ( tutorial video on my site. Might help clear things up.

03 March 2005, 07:05 PM
Thank you very much Carm3D. I downloaded the zip myself just now and it seemed ok. Would it not unzip at all. It's just done with XP which could be the problem. Yuk, hate XP.
Anyway, I removed the zip above and have reattatched a new one. Any luck???

Thanks again.


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