One of the challenges of working in 3D is visualizing where things are in the third dimension of depth. It can only be projected on to a flat 2D screen. In this lesson you will learn the difference between parallel and perspective projection. You will also learn how to change your point of view. Using preset views, the view cube an the navigation bar interfaces. Open the Cathedral One Project file, an then click here to open the View Controls menu. It contains a list of preset views, an they're categorized in two groups.
These orthogonal views and the isometric views. The word isometric literally means same measure. And it refers to the fact that all three coordinate axis appear equally foreshortened. You can see this here in parallel projection, where all three axis are equal. If we change to perspective projection, we get a subtley different, but very important change. If we were to trace the lines that are parallel to the coordinate axes off into the distance.
They would have eventually converge at a vanishing point. If we trace these edges here in the red direction off into the distance, they too would converge. And similarly, these vertical lines would converge at some point far below the screen in the green direction. So what we're looking at here is a three point perspective. This is the way that our eyes naturally see things because objects that are further away from us seem to get smaller. And so, I would choose perspective projection if I'm trying to present a design in the way that it naturally looks in the real world. However, when I'm working in AutoCAD, I often prefer to use parallel projection. This way everything shows it's actual size and nothing is foreshortened. If we switch to the front view again, you'll see that in parallel projection it's like an elevation drawing.
If I switch to perspective, it might look more realistic, but it's much harder to work here and snap to different points. I'll go back to parallel projection. Then I'll open this Adjacent menu, which is called the View Port Controls menu I'll choose View Cube to toggle this interface on. Here we can go to different points of view by clicking on many of these different interface elements. I'll click on this bar to go midway between the front and top views. And I can click on the word Top to go into that precise orthogonal view. You can also click on these corner pieces to go into isometric views, you can drag this ring left and right to rotate the plan.
You can also use this tiny menu in the corner to change your projection type. This is parallel. This is perspective, which is very subtly different. And then there is perspective with ortho faces. So this is kind of like a hybrid mode that gives you perspective when you're looking at it here in an isometric view. Or if you go to an orthographic view like the right face, it will switch to parallel projection.
There's also a menu here which allows you to change the coordinate system. And right now it says WCS, which means World Coordinate System. You can create a new UCS from this menu if you like. The WCS is the Default Coordinate System, and the UCS is a User Configurable Coordinate System. It can be useful to reorient or move the origin point of the UCS when working with 3D models, there are also arrows. Around the viewcube. And if you click on the arrow, it will rotate 90 degrees. Notice, also, that there are arrows out here that allow you to rotate the plan. If you click on the Home symbol, it will take you back to whichever view is defined as the Home view.
To define a particular view as the home view, go to it. And then right-click on this symbol and choose set current view as home. Next, let's go back here to the View Port Controls menu, and turn on the navigation bar. The navigation bar has steering wheel, pen, different zoom controls here in this fly out menu. And it also has different orbiting tools located here. Let's try Orbit first.
This allows you to drag and rotate the view in a freehand kind of way. Press Enter to end the command. A shortcut for that is to hold down the Shift key, and drag the mouse wheel, it does the same thing. There's also a free orbit variation and this allows you to orbit so that the vertical lines no longer stay vertical. And you can get, sort of, all mixed up, upside down and backwards, here, if you're in the free orbit variation, here.
I'll go back and say, Zoom Previous. Finally, there's continuous orbit. And the way that this works, is you click and drag, and let go. And the model will continuously orbit around and around. This can be good for a presentation. It depends on how quickly you drag. If I drag very quickly, it will orbit too fast. So you have to be careful about how you drag and how quickly you release the mouse I'll use the view cube to go back to a isometric viewpoint.
In this lesson you learned how to change projection types from parallel to perspective and back again. And how to view the model from all angles using preset views, the view cube, and the navigation bar.
- 3D views, perspectives, and tools in AutoCAD
- Controlling the visual style
- Working with tiled viewports
- Composing perspective views
- Drawing in 3D
- Modeling an Ionic column
- Documenting 3D models
- Creating dynamic slideshows, animations, and renderings