Multiple pivot points?

[Pat Pattle]

Hi all,

Am trying to animate an undercarriage leg. It has to rotate in 2 axis as it retracts (like a P40). Is there a tutorial anywhere that shows this please?
I've tried aligning the pivot to the leg thinking that this would do it but as soon as it's rotated in one axis the pivot point isn't right for the second.

Many thanks,

Clive

[hairyspin]

Hello Clive, maybe I know which model you mean? I think the problem is not pivot alignment but which Reference Coordinate System (RCS) you're using.

First make sure the pivot is correctly aligned - one axis along the gear leg, the other running through the hinge line, probably 90 degrees to the aircraft's centre line. Now look at the RCS drop-down box on gmax's toolbar at the top of the screen - by default it says View. Change this to Local. Rotating the gear back now leaves the pivot still aligned with the gear and swivelling the wheel 90 degrees a la P40 is the work of a moment.

Reference Coordinate Systems (http://www.cgarchitect.com/upclose/article5_TB.asp)are a vital tool in our armoury and the late Gerard pointed to an excellent article on this in his Low-Poly Tutorial (http://www.sim-outhouse.com/sohforums/showthread.php?16418-Low-Poly-Aircraft-Modelling-Tutorial), still here on SOH

[Pat Pattle]

Hi Tom,

Yes it's 'that' model lol. You're a star mate, that worked a treat. I knew the answer must be something as straightforward as that to fix but blowed if I could find it! Thanks also for the tutorial link, had forgotten that one.

Modelling the Harrow with it's fixed undercart is so much easier!

Thanks again.

Clive

[hairyspin]

Erm, a little correction. :redface: Changing which RCS is used changes how the Gizmo works, not the Pivot. The Pivot is a property of the object, the Gizmo determines how a move, rotate or scale operation affects the object. Using Local RCS aligns the gizmo with the pivot, which is what was wanted.

[Pat Pattle]

Ah! was unaware of the technical differences. Main thing is that it works! :)