Clothilde Splines By Jamie Hamel-Smith
Tutorial
Have you ever wanted to create a dynamic spline? A rope perhaps? Well the easiest way to do it would be to use The Dynamics Module. However, the Dynamics module doesn't do any sort of collision detection where splines are concerned. I have found a workaround to this problem through trial and error and a little bit of XPresso. We needed to create an animated hose for a gas pump and MOCCA IK wasn't cutting it. I already knew that Dynamics would not do the job of collision detection and such, and we don't own Dynamics, so I came up with this solution. I hope you enjoy my tutorial as much as I enjoy squashing these problems like bugs! The most important part of this tutorial is the Clothilde. Typically intended for things like clothes and sheets draped over things; Clothilde is also extremely useful for creating things like hanging tassels and the great thing is that it supports collision detection. I wanted to create a spline that moved like a 'Clothilde Strip' so that I could use a SweepNURBS Object to create a rope or hose. Here is how it's done; first thing we need to do is create a Clothilde strip that we can attach a spline onto. The best way that I have found to do this is as follows: Create an empty Polygon object from the Objects menu, Switch to the top view (F2) so that you can get a better view of your straight line of points. If you switch to the Points Tool and Ctrl-Click using the Move Tool in the view port, a point is created. This point's 'index number' is 0… ok I know what you are thinking, "Big Deal!" well, I want you to go to the Window menu and open the Structure Manager. In this window
you will see the points belonging to your object, it should only have one point right now of course, your lonely little "Point 0" well it is very important that we create the order of the points on this polygon object, because we will need to call on that order of points for a little favor when we get to the Xpresso stage of the tutorial. So obviously the next point will be point 1, and then point 2... We get the Idea. So we are going to create a vertical line of 10 points in our top view port. [Image 01]
Image 02
through 9 points in tact (having the structure manager open during this process will be a great help to show you what's going on.) After cloning all of the points, move them over just a bit. [Image 03] Ok, so now we have 2 nice rows of points that we
Image 01
Now we can't just apply Clothilde to any old set of points right? It has to be a polygon mesh, so we need to create another row of points. The point numbering of this second row of points is not important, so we can just select the first 10 points we just created and from the Functions menu choose the Clone function. Set the number of clones to 1 and set the rotation values to 0. [Image02] This will create an exact copy of all of the selected points that will be numbered 10 through 19, which is perfect because it has left our 0
27
Image 03
can turn into a Polygon Strip. Select the Bridge tool and bridge the points together to create a nice strip of polygons. [Image 04] Now we can add a Clothilde Tag to the polygon strip to make it dynamic! Go to the Object Manager and Right-Click the Polygon Object; choose Clothilde
