Cinema 4D / BodyPaint 3D Program Documentation Tutorials Animation Tutorial (basic)
Function available in CINEMA 4D Prime, Visualize, Broadcast, Studio & BodyPaint 3D

Timing and Interpolation

Frames per second

Timing plays a very important role in any animation. It is important to understand how to use timing in Cinema 4D to make the best out of your animations.

A sequence of frames represents a specific span of time. Depending on the output format used, the number of frames per second will vary. For example, the NTSC format requires 30 Frames Per Second (FPS) of animation and the PAL format requires only 25 frames per second of animation. To avoid having a different FPS for output than you do for your Viewport animation, make sure the FPS in the Project Settings... matches the frames per second in the Edit Render Settings... Output tab.

At 30 FPS, one second of animation consists of 30 frames. This means, that if you move an object along the X axis and set a keyframe every 30 frames it would take that object exactly 1 second to move from one keyframe to the next.

To define a frame rate, open the Render Settings menu (Ctrl/Cmd+b) and change the FPS value in the Output tab’s settings. To change the frame rate in the Timeline select the Project command from the Attribute Manager...’s Mode menu. The Timeline will also change slightly to match the new frame rate.

Types of interpolation

The Interpolation differs from the Frame Rate in that the spatial positioning of the keyframes is of importance. Interpolation makes it possible to control the velocity of an animated object between keyframes. With it you can define the time interval with regard to the distance the object moves. This correlation, as you can see in F-Curve mode, is very important for creating spatial movement.

The movement of the animated parameter can be easily recognized in the image below without having to play the animation. You can see how the curve changes over the length of the animation. The steeper the curve, the faster the velocity of the animated movement (a great change in value over a short temporal span). The flatter the curve, the slower the animated parameter changes.

In the following we will explain how the various types of interpolation work. By default, all keyframes use the Spline Interpolation mode. This automatically creates a soft transition from keyframe to keyframe with a slight subsiding of motion in close proximity of the keyframe itself. This results in an organic movement without much effort and is therefore defined as the default method of interpolation. The F-Curve for this type of Interpolation is displayed as a soft curve whose keyframes each have a handle that can be used to adjust the radius of the curve.

We also have the Linear Interpolation mode, which creates a simple, direct transition between keyframes. The keyframes are not assigned handles, which means the movement between keyframes remains linear, with a consistent velocity. This type of Interpolation is useful when the position between two identical keyframe values should be maintained.

Another method of Interpolation is the Step mode, which is entirely different from all other modes. With it, an object maintains its current value until the next keyframe is reached. This mode is very useful when creating on/off animations or for determining an object’s starting position or timing.

If you zoom in to a keyframe until its symbol can be recognized you will also see which Interpolation mode it uses in Dope Sheet Mode.

Use the Project Settings... to adapt your default interpolation in the Key Interpolation tab. These settings can be found in the Edit menu in Cinema 4D or in the Attribute Manager’s Mode | Project.

Here you can define how your default interpolation should look and function when keyframes are recorded, either manually or via Autokeying.

In practice, the various Interpolation modes look like they do in the following video. All three spheres have identical keyframes set but each has a different method of Interpolation:

 

The blue sphere jumps directly from point A to point B, without any noticeable transition. This animation was created in Step mode. The green sphere moves with a constant velocity, which is a typical characteristic of the Linear Interpolation mode. The red sphere was animated using the default Spline mode and its velocity is either accelerated or abates in the vicinity of a keyframe.

If you use the Spline mode you can adjust the tangents of the curves and influence the animation accordingly. We will discuss modifying F-Curves in the next section of this tutorial using practical examples, which will make the process easier to understand.

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