Path, Dupliframe and cyclic animation.

Path, Dupliframe and cyclic animation.

I am working on a project using a tracked vehicle.

I have made a single link for the caterpillar, and
I have made a Nurbs curve a normal parent of this link.
The Nurms curve is used as a path that goes around the wheels
and I have toggled the options Curve path and Curve follow.

I have set the right references for the axis.

When I run the animation with ALT+A, the link goes
around the path correctly.

I have toggled the dupliframe option for the reference
caterpillar link, and the link is now duplicated around
the path, making the caterpillar.

Problem 1 : when I run the animation, only the reference
link goes around the path, not the duplicated links.

Problem 2 : I don’t know how to loop the animation. I can’t join the end point of the path and the start point.
I’d want to get something like the option Extend mode-Cyclic
of the Ipos, but my animation doesn’t use Ipos.

Does someone have an idea to make it right ?

Thanks in advance.

Philippe.

First off : here an example made in 10 minutes from old memory.

Tell me if this is close to what you’re looking for.

Hey ! I didn’t know the expression ‘normal parent’ : as Theeth would put it, answering questiions is the way to learn. :slight_smile:

of this link.
The Nurms curve is used as a path that goes around the wheels
and I have toggled the options Curve path and Curve follow.

All is good, all is good…

I have set the right references for the axis.

BTW, this can be done simply by rotating the children in edit mode, every vertex selected. Much simpler than playing with the buttons in the Object context that are sometimes butt busting.

When I run the animation with ALT+A, the link goes
around the path correctly.

I have toggled the dupliframe option for the reference
caterpillar link, and the link is now duplicated around
the path, making the caterpillar.

Not really : those copies aren’t real and need to be made real (ctrl+shift+A if I remember correctly). Yet it is still to soon to do it.

Problem 1 : when I run the animation, only the reference
link goes around the path, not the duplicated links.

See above

Problem 2 : I don’t know how to loop the animation. I can’t join the end point of the path and the start point.

Not sure I fully get your meaning there : in the example I used a 2D nurbs circle which is a closed circuit. BTW you can close any open curve by selecting all of its vertices ans hitting the Ckey.

I’d want to get something like the option Extend mode-Cyclic
of the Ipos, but my animation doesn’t use Ipos.

…and yet you could and should. Give your first link a (likely linear) time IPO that goes from (1,1) to (100,100) ; those are arbitrary values ; make it cyclic extrapolation ; duplicate this link to create the others and they will likely (depending on the settings in your info window or your use of ctrl+shift+A which gives instances rather than copies) share that same time IPO. For each link make this IPO single user and offset it in time (drag along the x axis, holding ctrl preferably, for precision) You’ll se the link move.

You may (should) give the path a Speed IPO going from (0,0) up to (1,1) and extrapolate (I don’t think that cyclic is necessary).

Does someone have an idea to make it right ?

Thanks in advance.

Philippe.

Come back for details if I forgot any.

Jean

http://pages.infinit.net/bobois/track002.zip

There, I’ve added the essential tracking constraints.

Jean