## AutoCAD Tutorial : Session Six

*3dface and complex surfaces, edge, splframe*

**Open your model. Get a plan view, and make sure that all the layers that are not text layers are displayed. Freeze HATCH, GRID, and TRASH as well. **

**Make a layer called FACES, and make it the current layer. **

**We have been making combinations of lines, polylines, and 3D faces so far, but let's now make a figure that consists entirely of faces, surfaces. These are the kinds of figures we should make, in fact, when constructing 3D models. So let's begin by making a box, entirely constructed of faces, to contain all the horizontal and vertical rectangles we've drawn so far. **

*** Use the 3dface command to make a face with the following corners: 2.5, 8.5, -2; 7.5, 8.5, -2; 7.5, 1.5, -2; 2.5, 1.5, -2. * That surface will lie below all the lines and surfaces of the rectangle we've drawn. Now copy it and put the copy at an elevation of 2.5. * Now you have a top and bottom surface. Put sides on the "box" by using the 3dface command. Remember that you will want to use an isometric view and the osnap with endpoint option to make the sides of the box. * You should now have a six-sided box consisting only surfaces. To prove that there are surfaces, let's move around the box and see how it looks from various angles. Use the vpoint command to make views from 1,1,1; -1,-1,-1; 1,-1,1; and -1,1,-1. After generating each viewpoint, use the hide command to see how the box appears. You will find that the views from below the level of the box (the ones with -1 as the z-coordinate) to be very deceptive. But you should find that, in each view, the rectangles we drew before are hidden and the polyline is not, because it lies entirely outside the box. Part of the polyline will be hidden, because the box will be in front of it. * So far, we've only worked on four-sided boxes, quadrilateral shapes. Now let's try to make a box with five sides, one that contains the box we just drew (let's call it Box 1) but not the polyline. First, make a new layer called PENT; make it the current layer. Now let's make a 3dface using these 5 points: 1.7,1.3,3; 8.3, 1.3, 3; 8.3, 8.5, 3; 5, 11, 3; 1.7, 8.5, 3. (You will need to use **

*** Set the osnap to end so that you will be choosing endpoints in the following. Type ** 3dface and then select points in this order. Start on the upper pentagon, at the corner furthest from you (the SW corner), then pick the same corner of the lower pentagon, then the next corner of the lower pentagon (going clockwise), then the corresponding corner of the upper pentagon, then the next corner (continuing clockwise) of the upper pentagon, then the corresponding corner of the lower pentagon, the next corner of the lower pentagon (still clockwise), and so on until you come back to the first two points, which you will have to pick again. Type

*to see the results. If there are incorrect surfaces, it is probably the result of selecting points out of order. You should do this over again, if necessary, to get it right.*

**hide***** Now thaw again the layers HM, HB, HT, VR, VL, and FACES. (Remember, you could use H? and V? to get all the rectangles.) Use the hide command to see what happens. * Making larger surfaces can become rather complex. Let's see how to approach that task, using a polyline as the boundary so that we can re-work the surfacing possibilities without typing coordinates again and again. Return to the plan view. Draw a closed polyline (still on layer PENT) using these coordinates: 11, 9, 0; 10, 4; 12, 0; 15, 1; 16, 3; 15, 5; 13.5, 7. Now let's try to make a surface within the boundary of that polygon. (Remember that, once you specified an elevation for the first point, all succeeding elevations were determined, and no z-values could be entered after the first point of the polyline.) * First, zoom in to make the polyline occupy most of your screen area. * If you look at this figure, I think you will find that it would be impossible to make a surface with this boundary with a single 3dface command. We may be able to do it with only two, but we will want to use a feature we have not previously discussed. When using the 3dface command, typing I with a space or **

**Time to save and stop. **

**End of Session Six**

**---------------------**

source : http://www.digitalcad.com/Htm/tutorials/CSA_beginners_autocad.htm

## 0 Responses to "AutoCAD Tutorial : Session Six"

## Poskan Komentar