View Full Version : Adjust speed along motion path?

08-12-2014, 05:27 PM
I have a couple particle emitter nulls that are basically tracing around a yin yang. I drew a curve in Modeler with Spline Draw that yins and yangs around and ends up back where it started. I exported with Curve to Motion, and then in LW selected my Null and File/Load/Load Motion File and it animates my null nicely. If I set all the pos keys to Repeat, then it yangs around forever which is what I want.

But what I really want, is to now have a slider that controls the rate at which my Null follows that curve. So for most of my animation I can have my null yinning along the yang at 50 parsecs per second, but at key points I want to ramp it up to 12 parsecs per second and Kesel Run the [email protected]#* out of that yinyang.

How would I set that up?

I seem to recall seeing a tut where a dude had a space ship with like 10 moving parts animated and he some how rigged it all to be controlled with 1 null, but I cant remember any of the details.

Any tips would be appreciated as always.

08-12-2014, 05:54 PM
I use PathAnimationIA when I want to control the speed of a path. But I'm not sure that'll work in your case since you're looping your animation.

I suppose you could bake out your speed adjusted motion and then loop that.

08-12-2014, 07:40 PM
What you probably want to use is Cyclist. Cyclist is a Motion Modifer that lets you assign the animation of one or more objects to another object as a controller. I use this from time to time to do 'Transformer' style animations in films and commericals.

Using Cyclist is very easy: apply Cyclist to the animated object's Motion Options panel, set the range of frames where the animation occurs, select a controlling object and set any other appropriate settings. If you're controller is set to X, Y, or Z, the object will behave like a slider. If it's H, P, or B, then it works like a dial. Set the range of the controller to control your motion, which I thnk in your case would control the speed and distance of the emiiters. Once you set up the first instance of Cyclist, you can probably just copy and paste the same one for every other emitter. It's also a good idea to set limits to how far you can move or spin your controller object--you can do this for the controller object under the Controllers and Limits tab.

Somewhat related: there's a sister plug-in called Cyclist, which can do the same for envelopes--I use it to control a sequence of morphs. Cyclist is used the same way except it goes in the Graph Editor for the animated object(s). I won't help in this case but it's good to know about both tools. (Note: there is a bug in Layout that prevents morphs form being updated in realtime with this tool, but if you turn on Studio LIVE, it works. Just don't forget to turn off Studio LIVE when your'e done because it's a CPU hog. Also, don't turn on VPR and Studio LIVE at the same time--for reasons that should be obvioius, that's asking for trouble.)

You can also use the native Spline Control tool in Layout to move the emitters on a defined path. You can control the speed and distance by keyframing the Z position of the emitters. If you want to get fancy, you can use Cyclist to link the Z position for each emitter to your control object. But for something this simple, I usually just keyframe and adjust the Z positon in Graph Editor.

Hope this helps.


08-13-2014, 02:54 PM
Thanks guys. Unfortunately this project is in rush mode and we opted to skip the speed ramping, but I look forward to experimenting with these tools in the future...

08-13-2014, 03:01 PM
Whoops...I mis-typed. The motion modifer is called Cyclist but the one that goes in the Graph Editor is called Cycler.

08-13-2014, 03:06 PM
I'm surprised we're still using Cyclist for this function-- my impression was we had newer tools for this.

Nothing wrong with the tried and true, but just surprised.

08-13-2014, 03:16 PM
Yeah, I still use it. Cyclist is easy to set up and works reliably, especially for complicated mechanical animations. The only issue I've run into is when multiple copies of a rigged machine or vehicle (a spaceship with lots of animated weaponry for example) are brought into a scene and Layout gets confused and assigns the animation keys for all the imported instances to the original object's controller. There are workaround tricks to prevent this but it's really annoying.


08-13-2014, 04:38 PM
Ahhh, the old "we're using names instead of ObjectID" bug.

08-13-2014, 04:45 PM
Yeah. Sigh! :)

08-13-2014, 06:32 PM
related >