From the course: 3ds Max 2018 Essential Training

Choosing a coordinate system - 3ds Max Tutorial

From the course: 3ds Max 2018 Essential Training

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Choosing a coordinate system

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- [Instructor] In this chapter, we'll take a deeper look at manipulating objects. For the first couple of movies, I just want to use this very simple, primitive scene so that we can isolate these effects without being distracted by too much model detail. The first thing let's look at is reference coordinate systems. When you transform an object in 3-D, you have to have some point of reference for that transformation. In other words, if you move in X for example, are you moving in the X axis of the world or of the object itself? And those are often two different things. To change the point of reference for transformations, you'll go up here to the main toolbar and you'll see a pull down list that's labeled view by default. That's the reference coordinate system. Each one of the transforms, move, rotate and scale, has it's own reference coordinate system. If you change this pull down list for move, that does not change it for rotate. Each one is separate. All right, let's take a look. I'll choose the move tool, and to simplify things, I'm going to switch this over to world. Now the move tool is operating in world or global space. If I select an object, we get the move gizmo and we can see that it's oriented the same way in all of the viewports. In the front view, Z is up. In the perspective view, Z is up. In the left view, Z is up and so on. World is very simple. We're moving the object relative to the world grid. Let's try something else. We'll go to rotate and you'll notice that it's switched itself to view. Each one of these remembers the state of the reference coordinate system. Go back to rotate and let's choose local. In local rotations, we can orient an object relative to its own internal reference coordinate system. The way that we know that's happening is because as we rotate the object, the rotate gizmo is stuck to the object. All right, so I'm just going to turn this so it's a little bit interesting direction relative to the world. Now I'm going to go back to the move tool and we'll see, by default, in world space, Z is up. Let's switch this out to local and now we can manipulate and move the object relative to its own coordinate system. You'll see that the move gizmo is no longer aligned with the world. So I can go back to rotate and turn this around and do something interesting with it so it's turned in some extreme direction and then when I move in local space, we can see very clearly that the Z axis is no longer the elevation here. The cone is moving relative to its own Z axis. There are a bunch of other coordinate systems. We're not really going to go over all of them. The only one that I really want to cover for you is view, and that is the default one. View is kind of strange. It operates in the space of the viewport view plane itself. So if I select an object in the front view, we'll see the Y axis point up and the X axis over to the right. We're seeing something different over here in the top view. Until we actually activate that top view, and to activate that top view without losing the selection, we can right click. And now you'll see in this top view, Y is pointed up and X to the right. Same thing over here on left. If I right click, now I've highlighted that viewport, it's active, Y is up and X is to the right. The view coordinate system operates in the view plane of the currently active viewport, except in the perspective view. In the perspective view, when you're in view mode, you're actually operating in world space so Z is always up. Those are the three main reference coordinate systems you need to know right away. Local is the object itself. World is the global space and view operates in the plane of the viewport except in perspective view, where it defaults to world coordinates.

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