AutoCAD Tutorial : Session Five

copy multiple, array, mirror, bhatch

Open your model. Get a plan view, and make sure that all the layers that are not text layers are displayed.

Make a layer called GRID, and make it the current layer.

COPY MULTIPLE

* Making multiple versions of something is one of the things a CAD program does very well. Draw a line from -10,10 to -8,12 To copy that line, you know that you can type copy and make a new line in another place. You can also type copy and make many new lines in several places. But first you may need to zoom to be able to see the line you just drew.
* So select the line, and type copy.
* Then type m to indicate multiple copies.
* Now pick one end of the line (using endpoint) and indicate where the copies will go by typing @2,0, @4,0, @6,0, and @8,0. Then type another to end the sequence. You have just made four copies of the line, each two units apart.

ARRAY

An easier way to make multiple copies for a regular grouping of items is to use the array command.

* Type array and pick the last of the lines you just made (the rightmost line). Then you need to type to indicate that you have no more objects to select.
* You will be prompted for whether your array is to be rectangular or polar (rotational); choose r for rectangular.
* Then indicate that you want 2 rows and 5 columns .
* Then tell the system that you want the rows and columns to be 3 units apart. The results are similar to those we obtained with the multiple copy command, but we requested two rows and five columns. (The system counts the existing line as part of the completed array.)

MIRROR

Make your current layer VL, and freeze grid and trash. If you want to make a mirror image of an object instead of a copy, use the mirror command.

* Type mirror and select the polyline that surrounds the rectangles.
* Now you must choose a mirror line - a line that will mark the half-way point between the original and its mirror image. (This line need not be an actual line in the model, but may be a line implied by two sets of coordinates. In practice, you may need to construct a mirror line to use the command.)
* In this case, use an imaginary horizontal line tangent to the arc of the polyline at the top. To make such an imaginary line, type tan and select the top of the arc; then type @5,0 to define the end of the line. Now indicate that the original polyline should not be removed. Done! You may need to zoom out to see your handiwork, but you now have a image of the original polyline. (Note that the mirror image is on the same layer as the original, though the current layer was VL.) I have had trouble with the part of this process when I indicate the beginning of the tangent line. I'm not sure what happens, but it sometimes does not work correctly. If you have trouble, try again. It should work. If all else fails, make the mirror line first, use the mirror command, and then erase the line.

* Make layer EXP the current layer.

BHATCH

The command bhatch puts cross-hatching of some sort in a bounded area.

* Type bhatch.
* You will get a very complicated dialog box. The easiest way to use the command is to begin by picking a point in the model that has boundaries. (This is a 2D notion; so the lines that make the boundary in plan view may or may not constitute a true boundary, since they may be at different elevations. Lines that are not in a horizontal plane will be ignored. So it may be hard to get the results you want.).
* In the dialog box indicate that you are going to pick a point and do so, choosing one or more points that lie inside bounded areas.
* Then use the to indicate that you have picked the point(s) you want. The dialog box will reappear.
* Now, if you are using R12, pick hatch options to get yet another dialog box. (There are more to come!)
* In this one, you should pick patterns to see the available patterns (you can make your own if you don't like these).
* Pick one of the existing patterns (trust me on this, don't try to make your own yet).
* Having picked the pattern, you will see that in the hatch options dialog box there are indicators of scale, angle, and spacing. Don't try to change those now, but accept the defaults and select ok to go back to the BOUNDARY HATCH dialog box..
* If you are using R13, all the choices (except "advanced" are in the first dialog box.
* Select preview hatch to see the command. Try several possibilities to see what is possible before finishing the command with some part of the area hatched. Then make a new layer called HATCH, and put the hatching on it. Freeze that layer.

Make a slide of the current screen.

Save and quit. (You can always use end instead. I prefer to save as a separate process before quitting so that I can be more certain that the model has been saved before I have quit working. It also means that I am not in the habit of using the end command. That's good, because I don't want to save when I am only looking at a model rather than editing it; so the quit command is better there.)

End of Session Five.

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

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