Animating a linear screw actuator.

[lynxlab]

Hello,
I am trying to make an animation of a microwave antenna dish. The dish can be moved in elevation by means of a jack screw, which in the model looks like a bar attatched to the dish at one end and passing through a sleave connected to the rest of the antenna structure. Does anyone know how to tell lightwave that I want the bar to stay within the sleave at all times and to just slide in and out? In solidworks I just defined a concentric mating and all was good. Is there anything equivalent in Lightwave?
Thanks,
Glenn

[omeone]

I think, (hard for me to visualise without seeing it) in the model file - align the model so that the sliding bar is in-line with one of the primary axis (if it isnt already), then in Layout parent the sliding bar to the sleeve.
Lock the two translation channells that you do not want the bar to move on:
select the object
Hit 't' to go into move/translation mode
Click on the buttons on the bottom left of your screen (beside the numeric enrty boxes) to deactive them.

check this pic: the X and Z channells are locked
(and yeah the solidworks mating relations are pretty nice for working with)

[Mylenium]

You need to do the classical piston setup involving IK and two Nulls. Read something about it here:

http://www.splinegod.com

Mylenium

[omeone]

oops try that again

[lynxlab]

Can anyone provide more information about this? It looks very close to what I want, but I can't seem to get it to actually move and animate as expected, even though all the IK stuff seems to be set up correctly. The piston example is on this page: http://www.splinegod.com/rigs.htm

Thanks again,
Glenn

Originally posted by Mylenium
You need to do the classical piston setup involving IK and two Nulls. Read something about it here:

http://www.splinegod.com

Mylenium