Here's a tutorial based on part of an animation I did. This will explain how to morph a spline. There are many great reasons to morph a spline but in this case we'll be using it to deform and animate an object that was created by rotating the spline.

First, render out the project "SplineMorph.c4d" so you can see what our goal is or just click play in the time manger if you want a quick preview. If you want you can just follow along with this project as you do the tutorial and save the time of doing all the steps.

Start a new project. Use the Empty Spline Tool to create a new spline, I'm using a B-Spline here.

With the Points Tool selected control click to add points and draw a profile of a plunger.

At this point I zeroed out the splines position in the Coordinates Manager.

Duplicate this spline by option dragging it in the Object Manager, rename the new spline "MorphSpline". You don't have to name it "MorphSpline" but it does have to be a different name than the first spline.

Readjust the points till you have a profile of a compressed plunger.

Add a Lathe NURB to your project and set its coordinates to zero also. In the Object Manager drop the first spline onto it. It should now look something like this.

In the picture above I've already textured the plunger and disabled Show Isobaths, which you can change by double clicking the Lathe NURBS icon in the Object Manager.

Open the Time Line, Control click on Spline. In the menu that pops up select - New Track/Special Effects/Morph.

Control click again and select New Sequence. Enter the amount of frames you want the morph cycle to be and select OK.

Control click the timeline to add a keyframe at zero. In the dialog box that comes up type "s" and the program will quess "Spline" for you, select OK.

Adjust the keyframe so it is on zero if you missed and then option drag it to the end of the sequence so it leaves a copy at the end of the sequence. This is so the morph returns to its original state at the end of the sequence.

Control click the middle of the timeline. In the dialog box that comes up type "m" and the program will quess "MorphSpline" for you, select OK. Your Time Line should now look something like this.

Scrub back and forth in the Time Manager to see your morph in real time. If you're not seeing any changes make sure that you have the camera icon selected and Animation Effects checked under View/Display Mode/Options....

You should see changes like this.

If you're not happy with your shapes you can edit the points or positions of the splines at any time and the rest of your animation will not be affected. That's one of the great things about having an integrated NURBS modeler

Happy Morphing!