LESSON 3-4

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LESSON 3-4 - VIEWING 3-D OBJECTS AutoCAD has a few ways for you to view an object other than the plan view that you have used for your 2-D drawings. For quick, easy views use the pull-down menu options. To do this choose View > 3-D Viewpoint > (then select one of the four bottom isometric options). Look at the drawing below to see the differences between four views. When doing basic drawings, it is a good idea to use only one view. This will keep you orientated a lot easier. It is most common to use theSouthwest view, as this keeps your positive X and Y axes in a logical position. For most of your work in this course, stick with this view.  There will be times when you may need to see around to the other side of your object. Then you can easily use the other preset views to see your model. You can also have more than one view on your screen at a time. See below: To achieve this, use the Tiled Viewports option of the View pull-down menu. Then choose the New Viewports tab, and pick from several layouts. Any view or viewport configuration can be saved under a unique name. Later you can easily restore this view when needed. Here are the preset viewport configurations that you can use in model space. As you can see, you can select options for 2D or 3D, and change the view by picking in one of the viewports and selecting a new view in the droplist. Here are a few general notes about views and viewports: · You can have viewports in either model space (tiled) or paper space (floating). · They can have different zoom ratios. · There is a difference between views and viewports. · If you go to a lot of work to get a view you need, save it using the VIEW command. · When saving a view, give it a descriptive name. · Keep an eye on the UCS icon in the corner of the screen or viewport. · The smaller your monitor is, the harder it is to see tiled viewports. · When you have more than one viewport, click inside the one you want active. To practice viewing your 3D drawing, open up up this simple 3D file of a table and chairs. Change to different viewport layouts. Try some of the different Isometric views. Depending upon the size of your monitor, it may not be practical to use multiple viewports. In the end it is a matter of personal preference that decides what setup you are comfortable drawing in. Change back to 1 viewport (View > Viewports > 1 Viewport) and switch to the SW Isometric view. PERSPECTIVE VIEWS There is another command called DVIEW (Dynamic View) that gives you more control over the view of your object. It will also allow you to see a perspective view of your model. This can be a very confusing method if you don't have a system. What follows is my approach to creating perspective views. The basis of generating a perspective view is to have a virtual camera and target. Think of where you would like to 'stand' (the camera) and what direction you want to look at (the target). In this example, I want a view that gives me slight perspective view of the table and chairs. The first thing I need to do is draw a point for my 'camera'. Draw a line from the centre of the bottom leg 6' in the negative X axis. Now draw a line 5'6" straight up (@0,0,5'6) - and finally draw a line to the middle of the far end of the table. It should look like this: Now start the Dview command. You will be asked to select objects. You can select everything, or for the purposes of setting points, I would normally just choose the line as it makes the command faster in large drawings. Select the top line to the middle of the table.  Choose the POints option by typing in PO  Now you have to select the Target - pick the right endpoint of the line (use Osnaps) Next select the Camera - pick the left endpoint of the line. It will look like the line disappeared, but you now looking straight down it. Press to end the command. Start the DVIEW command again and select all the objects. In larger drawings, select the objects that furthest to the extents of the drawing (this will same time and let you know the limits of your view) and any objects that are critical to your view. What this means in that if you are using the command on a very large drawing, the DVIEW command can bog down (slow down) your system to a crawl. By selecting only the ones on the outside limits of your drawing, you will still be able to use the command quickly and efficiently. This time, choose the Distance option by pressing D . This option effectively zooms in and out while in a perspective dynamic view. Move the slider at the top until it is just right of the '1x' and then left click with your mouse. Note that slower computers will take longer to regenerate the drawing for you. While still in the Dview command, type in PA for the Pan option and move the table and chairs up slightly in the drawing area so that they are centered. And lastly, type in H for the hide option for a more realistic view. and then press . You will notice that certain commands do not function while in a perspective view. For example, you can not zoom or pan the usual way. I recommend that you don't edit your drawing in this view. To preserve this view that you worked so hard to achieve, type in V (for view) and select the New button and give your view a name. Now when you need to go back to this view you just type in V again, select your named view, press the Set Current button and press OK. If you are using this command on larger drawings, like a home or building, the same process is used, but you should create the camera location to be further away from the objects you want to view. Practice makes perfect and this command can take some trial and error sometimes to get it just right. In the end, it is a very powerful viewing tool. When practicing, save views so you can go back to them if needed - it will save you a lot of time.