Subtitles of the Movie

So we have seen that hierarchy is a way of getting one node to control another node. We saw that if we parent one transform node to another, it will, child will inherit transform information from the parent. If you look up here, at the right hand corner of the screen, you can see construction history on/off, construction history on/off button. I am going to create one sphere now with history off - now I am going to turn history on and create another sphere. So this one here has history and this one here does not. Now I am going to display UI elements attribute editor, and I am going to load attribute editor into my panel view, or my panel setup. If you look at this sphere that was created without history, you'll see that we have the shape node that's available in the attribute editor here. This is the shape node here, and we also got the NURB sphere transform node and nothing else really shows up. Watch as I take the other sphere that was created with history on, with that button turned on. We have the NURB sphere node, the transform node, the shape node and I am going to left mouse button here on the make NURB sphere node - this is the history or the node that contains information about the objects history. And what I can do is change information about how the sphere is made. I can setup the start and end sweep angle of the spheres manufacture in this direction. I can also change the size of the radius of the sphere, and I can change the sphere from a cubic sphere to a linear sphere, in which you cannot achieve a smooth surface. So I bring up history just because it's another way of setting up causal relationships, that is non hierarchical. It's sort of specific to the logistics of the way you might create something in Maya, and they call it history because one condition that you might have setup at a certain time, will influence condition at another time later. And hierarchy really has to do with a very purely mathematical as opposed to logistical relationship. So I am going to delete this sphere now, and I am going to take my attribute editor out, and I am going to go into my front view, and I have created a curve, I am leaving history on, and I am going to create a revolved surface out of the curve. And I'll go into my perspective view here. Because I have left history on, the curve here is going to influence the surface, there will be a historical or causal connection between the two. Here I have just the curve selected, and now I will go into a certain mode, component mode as we'll see. And I am going to change the shape of the curve and you'll see that the shape of the surface will correspondingly change, and that is a causal but non hierarchical, and therefore historical relationship. So, we see that hierarchy is more of a mathematical relationship between pivots, but a causal relationship, and history is a relationship still mathematical, but between items that you might create and associate in Maya specific ways - such as making a surface and in fact binding a skin, binding a characters skin to a skeleton, is a historical operation.