School of Motion

How To Animate Along A Spline In Cinema4D

  • By Ben Carmeli
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Cinema 4D Splines, those things that made you realize your days of struggling with the pen tool weren’t really behind you.

You probably already know about using the Sweep object with splines to quickly create pipes or rope in Cinema 4D. But did you know you could use splines to animate almost any object in your scene?

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Animating along splines is as easy as one, two, right click to add an align to spline tag and key frame the position value, three.
Collection

Easily create your own text reveal with the project file used to create the above gif

Let's Get Procedural

Why Should I Use Splines To Animate in Cinema 4D?

Okay okay I get it, you’re a purist. You wanna animate the X,Y, and Z values individually. Oh but don’t forget to add a hundred keyframes to continuously correct the orientation. Oh and when you’re all done with that, you can bet the client will come back and say that they never wanted a sphere it was always meant to be a cone! So let's look at why splines might offer a better alternative to this common problem. It's picture n' gif time.

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Two Identical cones performing the exact same animation. One using keys and the other with an align to spline tag.
Spline tag compare.PNG
aaaaanddd this is a look at the timelines. Notice the difference? It's okay, it's kinda subtle.

By using a spline to define your motion path, you’re free to interactively modify it in a way that keyframes just aren’t. You can then easily transfer or copy the Align to Spline tag onto any other object in your manager. Of course, there will be times when manual XYZ keyframing will be necessary, so this method isn’t going to completely save you from that, but it's a great option for speeding up quick animation work.

Okay, I've Got The Splines. But How Do I Use Them?

You’ve got a couple options when it comes to doing this, the Align To Spline tag and the Cloner object.

Pro-Tip: For best results when animating anything along a spline, be sure your spline is set to Uniform interpolation. This will create evenly spaced vertices which will result in smooth, predictable motion when animating the position value in either the tag or cloner.
Uniform_vs_adaptive.gif
The blue cone's motion is jerky because it's animating along an adaptive spline. It's also jerky because it doesn't call its mother regularly.

Align to Spline Tag

Using Cinema 4D’s tag system is very easy, and a big step toward realizing the program’s full potential, as many of it’s best features exist in tags. For the Align to Spline tag, we’ll simply right-click on the object we wish to animate, and go to Cinema4D Tags > Align to Spline. Now you won’t make any magic happen until you feed the tag a little bit of information.

First, you’ll select a spline to align your object to. This spline can be open or closed, it can be one of the spline primitives or one you drew from scratch, you can even use splines that have multiple disconnected segments. Once you’ve done this, your object will snap to the starting point of your spline.

tag_spline.gif
Aligned objects cannot be moved off their splines

Next you’ll want to pay attention to the Position parameter. This value is presented as a percentage, with 0% representing the start of your spline and 100% representing the end. Keep in mind, if you are using a closed spline 0% and 100% will represent the same position. Segment is an integer value indicating which spline segment should be used.

tag_position.gif
This would be at least 10 keyframes the old way!
tag_segment.gif
Behold! The possibilities!

Tangential will continuously orient your object so that it is parallel with the direction of the spline at any given point. Once you check this box, you will be able to choose which axis to orient parallel to the spline using any of the options in the scroll menu.

Tag_tangential.gif
Ok now we've saved about 30 keyframes

You’ll also have the option to use a Rail Path. Think of the rail path as the second rail on train tracks, or a roller coaster. If there were only one rail, the cart would be aligned with it, but could rotate around it. The rail path is often a path that runs parallel to the main spline, which constrains the objects rotation. I know I know, it’s gifsplenation time.

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Adding the rail to the object on the right 'locks' it's orientation as it animates along the spline

You can get really far without having to use rail splines but some situations call for the extra control only they can give you such as in this example from Pixel Lab.

Cloner Object

The undoubted rock-star of Cinema4D, the Cloner Object proves itself a surprising option in the task of animating objects along splines, let’s see how it’s done.

Parent your object to a Cloner set to Object mode. Then drag the spline you want to animate along into the Object field. This will create a series of new parameters.

Distribution lets you choose how your clones will be distributed along a spline.

  • Count lets you enter the total number of clones you want across all spline segment.
  • Step lets you enter in the distance between each clone. Therefore, the larger the step value, the fewer clones.
  • Even distribution works just like Count, except will maintain an even distance between each clone along the entire length of the spline regardless of the interpolation setting on the spline.


cloner_distribution.gif
This is a jam-packed gif so take the time to play with these settings on your own.
  • Offset allows you to shift all clones a percentage value along the spline, with offset variation randomizing the effect of that shift.
  • Start and End will fit all the clones within the designated range along the spline.
  • Rate allows you to set a percentage/second offset for each clone. You can think of this as speed, and with a little variation, you can create seemingly complex animations in very little time.
offset_Rate.gif
Okay, last time, about 2 million saved keyframes.

Now you’re animating without having set a single keyframe! And of course, this set-up is still extremely flexible, allowing you to swap geometry, clone counts, splines, etc. Oh, and you can now also use Mograph Effectors to add some random secondary motion.
So, now you’ve got your army of marching clones. What you do with that power is up to you.

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School of Motion neither condones nor endorses the use of clones for galactic conquest.