In this lesson I’ll show you how to use the Hatch command. As an example, I have chosen a mechanical drawing, which is normally among the files for the exercise, so it will not be difficult for you to repeat the whole process.
I will start by zooming in on the detail in the upper part of the drawing. Since I did it in the simplest way – by turning the wheel on the mouse, I did not manage to guess the exact scale, so some details “escaped” from the screen. So by pressing the Z and Enter keys, I will start the Zoom command and with another Enter, I will switch to a mode that allows me to directly specify the desired magnification. Now I just need to press the left mouse button and drag it down, until all the details that make up this part of the drawing appear on the screen. In the end, all I have to do is place them in the middle of the screen, and this can be easily achieved by using the Pan function, by pressing the wheel while moving the mouse.
I had to do all this for one simple reason. Namely, the Hatch command can automatically determine the boundaries of the future hatch, but it is necessary that the entire area is displayed on the screen. This means that hatching this rectangle will only succeed if all of its edges are visible. Otherwise, it may happen that the program misinterprets their position and cancels drawing the hatch.
Having made sure that this is not the case for me, I can select the appropriate icon from the Draw palette and run the Hatch command. After that, a note will appear next to the cursor – Pick internal point, which means that I am expected to select the position of the future hatch. If a different message appears, Select Object, simply click on the Pick Points icon and activate the appropriate mode. After that, you only need to place the cursor in the appropriate position and AutoCAD will do its best to clearly show you the selected surface. In some cases, this will not be possible, for the simple reason that there are too many elements in the drawing, so it is very difficult to determine the first boundaries. That’s why it’s best to start with simpler segments and avoid such problems.
Although there should be no problem in this part of the drawing, the program apparently ignores one line and automatically fills in both segments. To check what it is about, I will enlarge this detail a little more and repeat the same process a few more times. Unfortunately, I seem to be really unlucky this time, as there is no apparent reason for this behavior. On the other hand, it is not bad to keep in mind that the automatic border determination algorithm is not infallible and that sometimes alternative methods have to be applied.
I would like to place the hatch in this zone, regardless of the fact that no Preview is displayed on the screen. So I will click on the appropriate area and check what I have achieved. As you can see, in this case everything turned out quite correctly, but it could have been different. In other words, there are also situations in which such a notification appears on the screen after selecting the appropriate point. This means that AutoCAD was unable to determine the boundaries of the future hatch because the elements surrounding the selected area do not form a closed contour. In this case, there is a small gap between these two lines, and this is an insoluble problem for AutoCAD.
If you look a little closer at this hatch, you’ll notice that it corresponds to a pattern called ANSI31 in AutoCAD. If that doesn’t suit you, you can simply choose any of the offered samples, and if you want to see the complete offer, click on the arrow in the lower right corner of this section. At that moment, a large number of new samples will appear on the screen, so it will not be difficult for you to make a final choice. In addition to hatches that imitate certain materials, different types of gradients are available as well as patterns that correspond to the ANSI standard.
The hatch I’m currently using is obviously too small, but that can be easily fixed as well. It is enough to increase the value of the parameter related to the scale, to enter 5 instead of 1 in this field and press the Tab key. This is already much better, and if you want to experiment, feel free to change the parameters related to the angle and the transparency of the hatch (Hatch Transparency). In this way, you can prevent the lines that make up the hatch from becoming dominant in relation to other content, which in some cases has a very positive effect. It is precisely for this reason that I will place the parameter that controls the transparency somewhere in the middle, because I would not want anything to compromise the readability of the dimension lines.
There is even an option to choose different colors for each hatched area. I like the lines to be blue and the background orange, so I’ll apply the appropriate parameters and check what I’ve achieved. Unfortunately, this combination didn’t turn out very well, so I’ll go back to the transparent background and match the hatch color to the other elements on the same Layer.
If you want to transfer this element to another Layer, open the Properties palette and select the appropriate item from it. I have the Use Current option selected, which means that the hatch is on the currently active Layer, and it would be much better to use a separate layer for that purpose. So I’m going to select Hatch from this list and change the layer that this hatch is on. This will also affect its color because the rule that the color of the element is automatically adjusted to the Layer still applies.
If you want the lines representing a hatch to start from a specific point, click on the icon labeled Set Origin. After that, you only need to click on the appropriate position and AutoCAD will automatically adjust the hatch itself. I often use this option to draw floor tiles, because that way I can control their position.
You must have noticed that when hatching this area, AutoCAD cleverly bypassed the circle in the middle. The parameter found in the Options palette is responsible for that, so I will display its contents and immediately click on the third item – Island Detections. As you can see, the Outer option is currently selected, which means that the hatch will only be placed in the outer zone. If I change this parameter to Normal, the hatch will be placed alternately, and this can be concluded from its icon. You have already seen the Outer option, so I will immediately go to the third option and turn off any division with Ignore. As you can see, in this case, the hatch will occupy the entire surface, regardless of the arrangement of the elements on it. I like the first system the most, so I will activate the Outer option again.
The last option in this palette – Gap Tolerance, allows you to increase the tolerance for possible connection errors. I have already drawn your attention to the problem in this zone (impossibility of automatic border determination), so I will try to solve it by increasing this parameter. If I then click on this field, AutoCAD will inform me that it is still unable to create a closed contour so I have to try another way.