Tips for using pruning and stretching in CAD drawings

The trim command in CAD is a command that is used very frequently in editing commands, with the extension command and the trimmed command effect reversed, two commands can be converted to each other by pressing the SHIFT key during use. Trim and extend by shortening or lengthening the drawing, deleting the extra parts of the graphic, and making the shape meet the edges of other shapes. Because there are two commands, we can draw a graphic without particularly precise control of length, and even use construction lines, rays instead of straight lines, and then trim and extend the shape to rest.

I. Basic operations for pruning and stretching

The basic technique of trimming and stretching is to choose First, to select the trim, extend boundary, or cut object, that is, to select the object to be trimmed and stretched, and then to select the object to be trimmed or extended, and to master the selection techniques of both the pruning and stretching operations.

Trimming and extending related objects

Use the simple diagram above to first understand the pruning and extension of the basic operation, the following steps:

1. Input TR command, enter.

2. Click the selected Boundary object and enter.

3. Click in the top half of the trim object to complete the trim.

4. Hold down the SHIFT key, click the object you want to extend, and complete the extension. The results are as shown.

This is one of the most basic operations for pruning and stretching, and it is important to note that when you first start learning:

1, note the command line prompt, because the boundary object can select more than one, you must press ENTER or a space to confirm the subsequent pruning.

2, in addition to know that the pruning can also extend, do not need to exit the pruning command to perform an extension command again.

3, trimming the boundary can also be trimmed as objects, trimmed by other boundaries.

Second, the choice of pruning skills

Pruning extensions not only support some simple point and box selection, but also support some very special options. Master the choice of skills, can make the operation of the pruning efficiency doubled.

Trimming boundary objects (cut objects) supports a variety of general selection techniques, click, box, and continue to accumulate selections. Of course, the simplest option is to press the space (carriage return) key when the clipping boundary is selected, and all the graphics in the graph will be trimmed for editing, so we can trim any object in the graph. It's easy to manipulate all objects as pruning objects, omitting the option to trim boundaries, so most designers are already accustomed to doing so. However, the proposal is specific to the specific treatment, not in any case is in this way.

I find it inappropriate to use all objects as trimming boundaries, for example, to trim the yellow line between two red lines, and if you select all objects as trim edits, you need to point five times when trimming, and if you select only two red lines as the boundary, you can trim them only once.

In another case, if the graph has a lot of graphics and the number of objects is tens of thousands of, it is not recommended to use all objects as trimming boundaries when trimming. Consider that tens of thousands of objects are involved in pruning calculations, and it is certainly more expensive to consume more system resources than just selecting a few boundaries for pruning, which can take longer to calculate the software.

The trimmed object supports point and box selection, both of which can be used directly without input parameters. (earlier versions of CAD may not be directly selected, you need to enter options). There is also a special pattern for the trimmed object: the fence (F), which can pull a line, and the part that crosses the sub-line is trimmed, as shown in.

For this diagram, it is possible to choose two times for the box, which is more convenient than entering the F parameter and then pulling a polyline. If the part to be trimmed is in the middle of a line that is close to two, especially the diagonal, it is convenient to use F, as shown.

Third, edge and projection mode

In addition to the techniques selected, trimming and stretching provide options such as selecting Edge mode and projection mode.

Even if the selected cut or edge edges do not intersect the trimmed object, the extension lines can intersect, as shown in.

We will use the small vertical line in the figure to trim the slash, select only after the trim boundary is selected, when the command prompt:

Select the object you want to trim, or hold down the Shift key to select the object you want to extend, or [bar selection (F)/window intersection (C)/projection (P)/Edge (E)/delete (R)/Discard (U)]:

Enter e at this point, you can set the edge mode to extend or not extend, as long as the set to extend, you can use the trimming extension line to trim, if the settings do not extend, of course, cannot be trimmed, as shown in.

　　

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As for the projection mode, it is rarely used, mainly when two lines do not intersect, but in the case of intersecting views or other projections, projections can be used to trim them. For example, a line on the XY plane, the other line has z coordinates, in the top view it looks like two lines intersect, in fact, two lines do not intersect at all, in this case, if you choose "No projection", you will not be able to trim, if you choose the "view" projection, you can also use the UCS projection.

Specifies the projection method to use when trimming objects, and here are a few paragraphs from the AutoCAD Help, which you can try if you don't see it. Example diagram in order to make it clear, two viewports are set, one is an orthographic view, the other is an axis view, and the trimmed state is clearly visible by looking at two views.

No

Specifies no projection. This command trims only the objects that intersect the cut edges in the three-dimensional space.

UCS

Specifies the projection on the XY plane of the current user coordinate system. This command trims objects that do not intersect the cut edges in the three-dimensional space.

View

Specifies the projection along the current view direction. This command trims the objects that intersect the boundaries in the current view.

Iv. deletion and abandonment

Delete: Deletes the selected object. The input r option provides an easy way to remove unwanted objects without exiting the TRIM command. Select the object you want to delete or < exit: Use the object selection method and press ENTER to return to the previous prompt

Discard: Enter u to undo the last modification made by the trim or extend command.

V. Trimming and extending the bandwidth degree of the polyline

If you trim or extend a tapered two-dimensional polyline segment, the trim retains the current width, and if it is extended, the width of the line will extend the original taper to the new endpoint as the original trend changes. Of course, if the endpoint is negative when it extends to the end point, the end width is forced to 0. Zhengzhou Vitiligo Hospital http://www.51zhaoji.com/

Clipping and stretching are all based on the centerline of the polyline, that is, trimming at an intersection point with no width, the endpoint is always perpendicular to the polyline, and when the width is large, and the trim boundary is not perpendicular to the polyline, you see that the end of the polyline is partially stretched out of the clipping edge, as shown in.

　　

Vi. trimming and extending spline fitting polylines

Trimming a spline to fit a polyline deletes the curve fit information and changes the spline fit segment to a normal polyline line segment. Polylines that extend a spline fit add a new vertex to the control frame of the polyline.

Tips for using pruning and stretching in CAD drawings