In this lesson, we will study the trim / lengthen and learn how to correctly cut the lines with its help.

The command allows you to trim the lines specified by the user relative to the objects previously selected by him, or vice versa - to stretch the lines of arcs or segments to a certain primitive in the drawing.

First of all, the program will ask you to select objects. Important ! First of all, we select not the objects that we will shorten or lengthen, but the one relative to which we will trim.

After selecting the base object, press RMB and indicate those segments that you want to crop or lengthen. Important ! If we are cropping objects, then we need to point to that part of the line or arc that we want to delete.

Pay attention to the hint in the command line or dynamic input: when you press the Shift key and select any object, we will extend it if we originally selected the "crop" command and vice versa.

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When building, very often fragments of segments, arcs, etc. are found that have "crawled" beyond the boundaries of objects, the question arises of how to cut the lines in AutoCAD. To trim such fragments in AutoCAD, use the "Trim" command. Lines, rectangles, splines, rays, etc. can also occur as clipping elements.

Trimming in AutoCAD is carried out by specifying the so-called cutting edge and a fragment of the object, which, after crossing this edge, must be removed.

The trim command in AutoCAD, like other Editing commands in AutoCAD, is very popular and easy to use if you study it in more detail. You can call the "Trim in AutoCAD" command in several ways, as always:

1. On tab "Home" → panel "Editing".

2. By entering a keyword "OBR" and then pressing "Enter".

So all the same, how can you crop in AutoCAD? To answer this question, you need to consider the components of cropping: how to crop lines in AutoCAD, how to crop an image in AutoCAD and how to crop an object in AutoCAD, and learn general lessons or the basics of how to work with AutoCAD. First you need to select the cutting edge (or edges), and then you will have to select the objects to trim.

Let's give an example of how to crop an object in AutoCAD: let's say you need to crop a part of a segment that has gone beyond the rectangle. In this case, the cutting edge will be the rectangle itself, and the trimmed object will be the part of the segment outside the rectangle. I presented the whole process in the figure.

There can be many cutting edges, as well as trimmed objects. For example, I sometimes select all or most objects as cutting edges. And then I click LMB on those elements that I want to crop. Immediately after specifying an object, it is trimmed. You can end trimming by pressing the "Enter" or "Esc" key. Parts of the cutting edges themselves can also be trimmed objects.

By the way, if, when choosing cropped objects, the selection is made with the “Shift” key pressed, then the objects will not be cropped, but lengthened.

When choosing objects to trim, you can use the following options:

✗ Line and Secramka- allow you to select clipped objects using a temporary broken line and a cutting frame.

✗ Edge- enables / disables the mode of continuation of the edge to an imaginary intersection.

When this mode is enabled, trimming in AutoCAD will be performed even in cases when the trimmed object does not explicitly intersect with the cutting edge. Whether this mode is enabled or not can be seen from the command line prompt when calling the "Trim" command in AutoCAD.

If it says "Edges = No Continue", it means that the mode is turned off. You can enable it before selecting the trimmed objects by entering the letter "C" in the command line (or simply from the keyboard).

✗ Cancel- an option that allows you to cancel the trimming of the last object without canceling the entire command execution.

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2.2.2. Deleting Individual Drawing Objects Using the Erase Tool

Now we will consider an example of creating the same drawing, but in relative polar coordinates. However, you must first delete the previously created drawing objects. To do this, you can use the command you are already familiar with Erase in mode Everything, however, this time we will look at the methods of using the tool Erase to delete individual drawing objects.

1. Select from the menu system the command Change? Erase... The pointer changes from a crosshair to a small square called a signpost... When it appears on the screen, it means that the pointer can be used to select objects in the drawing. Also pay attention to the command window: it now prompts you to select objects.

2. Place the marker on one of the lines and click - the line changes from solid to dashed. This process is called drawing object selection.

Note. To make it easier for you to understand which line the marker is on, AutoCAD temporarily highlights it with a thickened outline. In our case, this is not essential, however, in complex drawings, this greatly simplifies the task of selecting the desired objects.

3. Do the same with the rest of the lines.

4. Press Enter to complete the selection and apply the command to the selected objects. Erase... The rectangle you created will be removed from the drawing, and the command Erase will end.

The last stage in the construction of the drawing is the final design of the contour of the technological groove. Of course, this problem could be solved by using the tool four times Pairing(using the tool Similarity to create the upper horizontal line of the groove contour). However, we will look at another tool that will allow us to solve this problem a little faster. This tool is called Trim and it is designed to cut lines protruding beyond other lines or drawing objects. As with the tool Lengthen, trimming is done in two steps. In the first step, construction lines are selected because the lines are trimmed before crossing them.

1. Run the tool Trim by clicking the button Trim panels Change or by choosing the command from the menu Edit »Crop or by entering the command in the command window Trim or simply arr... As with using the command Lengthen, AutoCAD in the command window prompts you to select the objects, which in this case will be used as cutting edges.

2. Select the two vertical lines created with the tool Similarity, which designate the right and left vertical boundaries of the contour of the technological slot (Fig. 2.20) and press Enter to complete the selection.

Rice. 2.20 Lines selected as cutting edges

3. Select the horizontal line that denotes the lower contour line to the left or right of them (Fig. 2.21).

4. Repeat the operation described in step 3, but this time select the remaining segment of the bottom line protruding beyond the other cutting edge.

Rice. 2.21 Selecting the right segment of the bottom line of the trimming slot

5. Press Enter to complete the command Trim... All we have to do is create the top line of the groove contour, and then cut off the tops of the lines that we just used as the cutting edges.

Note. Undo a failed command Trim you can by entering in the command window Cancel or simply O or by clicking on the button Cancel toolbars Standard.

6.Using tool Similarity move the bottom line of the groove outline up 30 units.

7. Run the tool again Trim and select the just created upper horizontal line of the groove contour as the cutting edge (Fig. 2.22).

Rice. 2.22 The upper horizontal line of the groove contour is selected as a secant edge

8. Pressing Enter to complete the selection of cutting edges, when prompted by AutoCAD to select the lines to trim, first the left and then the right vertical lines, as shown in Fig. 2.23. AutoCAD will immediately trim the selected lines.

Rice. 2.23 The left vertical line has been cut off, now it is the turn of the right

9. Press Enter to complete the command Trim... Comparing the result obtained (Fig. 2.24) with the original drawing (see Fig. 2.2), we see that the set goal has been achieved. A few of the simple tools learned in this chapter will come in handy more than once, not only in the rest of the chapters in this book, but also in your day-to-day work with AutoCAD.

Rice. 2.24 Final view of the drawing

If you feel that you are not quite confident with the instruments With lines, Similarity, Erase, Pairing, Trim and Lengthen, you can try to repeat the creation of the considered drawing a few more times. In AutoCAD there are no correct and incorrect methods of obtaining the result - you can apply a different sequence of drawing creation or a different sequence of using tools, different from the one suggested by the author. Alternatively, you can try to execute the drawing by launching all the tools by entering their aliases in the command window.

With some practice, you can close AutoCAD without saving the drawn drawing. To do this, select the command from the menu File »Exit or just press Alt + F4. (If you do not want to exit AutoCAD, simply close the current drawing by choosing the command File »Close or by pressing Ctrl + F4.) When prompted by AutoCAD to save the drawing, click Not.

You are now ready to study the material in the next chapter, in which we will talk about the next problem. The object that is shown in the drawing we just created has dimensions of 470 by 400 units. In this case, we can assume that we are talking about millimeters. However, such an assumption can not always be made. For example, if we have a drawing of the shaft of an electric generator with a length of 10 units, then how long does this part actually have: 10 mm, 10 cm or 10 m? In addition, the drawing of the office curbstone corresponds to the default dimensions of the AutoCAD window, so we did not have any problems in this sense either. But imagine that you really need to create a drawing of a 15-meter shaft of an electric generator with a diameter of several meters! Finally, if you create a drawing for foreign partners operating not in metric, but in British units, you willy-nilly have to create a drawing not in meters and centimeters, but in feet and inches. Therefore, in the next chapter, we will talk about how to adjust the drawing parameters according to the task facing the AutoCAD user.

It is very common practice to use bitmaps in AutoCAD drawings. Images can be used as underlays, illustrations, layouts for drawings, etc.

An image inserted into a drawing often needs to be cropped to fit into existing geometry. AutoCAD Standard Tool - Command CUTTING (_XCLIP)- allows you to select a polyline, a polygonal freehand and a rectangular contour as a clipping contour

Result of trimming with polygon and rectangle

How to trim around a circle? Obviously, this can be done using a polyline. There are two ways: 1. create a circle from a polyline; 2. create a regular polygon. It will not work to draw a simple circle from two arc segments of the polyline - such a primitive cannot be a contour for cutting.

Rounded polyline

1. Draw a rectangle of the required size (remember that the command Rectangle create a polyline of a special type)

2. Run the command for editing polylines POLEDIT (_PEDIT), select our rectangle and select the option Spline

3. We get a rounded spline

4. As a command option CUTTING (_XCLIP) select the resulting spline and you're done!

Regular polygon

1. We build POLYGON (_POLYGON) with a lot of sides. How many sides are needed? The question is solved in each specific case - it is necessary that the polygon looks like a circle. Don't overdo it - in most cases 50-60 sides are enough.

2. As in the previous method, as a clipping path, select a polyline and indicate our polygon