If you have two animated objects and you want to connect them together with a spline that will react dynamically when the objects move, then this tutorial is for you. Like most things in Cinema 4D this is very simple to set up, watch the tutorial below or read on to figure out how to do this.
For a quick step by step walkthrough on how to do this, or if there is one little nugget of information I skipped over and you don’t want to watch the whole video again to remember what it was I said, here we go.
First, you’re going to need an object you want to attach your spline to, I’m going to leave this one to you – in my example I had a bass guitar attached to an amp. You can have some rope, a robotic arm that you want to connect some hydraulic hoses to, whatever it may be.
Second, you need to create your spline. In my opinion a linear spline is going to get you the best result a majority of the time, but it really depends on what you’re making. A way to decide is like this – If you want a big long cable like a mouse cable, power cord, guitar cord, or a rope then I think you should go with a linear spline. With the linear spline you can evenly and easily add more points which will give you more natural looking deformation. If you need something to already be in a specific shape, like a hydraulic hose for example, then you should probably be using something else like a bezier spline.
When you create your spline and if you need to add a few more vertices to it what you’ll need to do is go into “point” mode, select all of your points with Ctrl+A (or Command+A on a mac) then right click on one of the points and click on the little box next to “Subdivide.” (see the picture below) And decide how many more points you’ll need (you usually don’t need to many, but it’ll vary depending on how long you’re cord is)
The Third step is to actually tell our spline to connect to an object. To do this add a “Contraint” Tag to your spline (Hair Tags > Constraint). Choose what object you want to constrain to and drag that object into the “Object” slot in the constraint tags properties. The next step is the important one, you have to choose what points of your spline are connected to this object, so go into point mode a choose the point you want and then back in the Constraint tag click the “Set” button. You’ll see a little yellow line connecting your point to the center point of the object you’re constrained to. If you need to constrain different points to different objects then all you have to do is add another Constraint tag to your spline and do it all again.
The fourth step is one that if you forget to do makes everything else we just did pointless, it’s to actually make your spline dynamic. This is easy – All you have to do is right click on your spline, go to “Hair Tags” and choose “Spline Dynamics.” From there you have all of the properties of the dynamics to play with, elasticity, drag, elasticity, stiffness, etc. And you’re done. Hit play on your timeline and look at your spline go!
A couple more little things to do after this is to add a sweep nurbs to give your spline some thickness, and you’ll also usually need to add a hyper nurbs onto the sweep nurbs to get it looking nice and smooth.
Hopefully that helps you get this working the way you want. If you have any problems or comments feel free to leave a comment below and I will do my best to help you troubleshoot.