In this session, we are going to show you how to create a complex and very cool dynamic nCloth simulation using any polygonal object. Let"s go ahead and jump right in.
Recently, I was asked to create a couple effects, one of a layer of paint peeling off the surface of a car as it screams around a track, and another was for creating an ocean of animated tiles.
Normally, I might create these kind of effects using particles with instanced geometry, with some simple expressions controlling the transforms and other behaviours.
Or instead of using standard particles, I might use nParticles because they offer a much higher level of control due to additional functionality like stickiness, lift and a host of mappable attributes, and while nParticles could take me a long way there, they are often quite unpredictable, and wouldn"t give me the type of physical behaviour that I wanted.
I am going to show you the simple yet little known technique (unless you are are a modeller), that I used to complete both of them---on time, on budget...oh yeah, and looking good. I know you will also find it useful for doing all sorts of different effects.
First, be sure you are working in centimeters by hitting the Animation Preferences button and down to settings. Lets also set the frame range to 300 frames.
You"ll want to start by creating a polygon plane by coming up to the polygon menu, over to create/polygon/plane...and set it to 25 units by 25 untis. We"ll also subdivide the plane by 200 in X and 200 in Y. This gives us a plane with 40,000 square faces. That"s a pretty high resolution, and some of you may get a warning message...Go ahead and go for it, or you can always use fewer subdivisions, it just wont be as cool.
We are using a polyPlane for simplicity"s sake but keep in mind that you can use this technique on any polygon mesh and I"ll show you an example of this later, but remember the higher the subdivions, the longer your simualtion will take to complete.
Finding the delicate balance between simplicity and performance is always a challenge, but that is where the fun lies in creating good looking, efficient effects. And that"s why I really like this approach.
The first thing we need to do is separate the faces in our polyPlane because instead of simulating the plane as a single cloth object, we"re going to simulate each of the faces in our ncloth mesh individually. Here"s the way to getting that accomplished.
Select the polyPlane and right click to enter component selection and select vertex or edges either one will work for this. Drag a selection around all the vertices or edges in the polyPlane. Then, come up to the polygon menu set, and over to edit polygons and down to detach component. This may take a few seconds.
You now have 40000 faces separated within your SINGLE polyPlane object. The mesh is now ready to convert into an nCloth object. With the mesh selected, under the nDynamics menu set, come over to the nMesh pulldown/ and select create nCloth.
Ordinarily, trying to simulate 40000 ncloth objects or more would be next to impossible, so we need to make a couple of very important optimizations. With the ncloth object selected, in the attribute editor under the collisions tab...uncheck self-collision and collisions.
By turning off collisions, you are maximizing the efficiency of the nCloth solver and tapping into some performance that might surprise you. This will allow the nCloth peices to simulate dynamically while ignoring each other and other objects in the scene.
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