A bit of a long one this week, but well worth sticking with it………..

The Basics to AutoCAD

Part 14

This time we are going to be looking at the ARRAY command. What is an ARRAY? Well AutoCAD defines it as, copies of objects in a rectangular or polar (circular) pattern called an array.

For rectangular arrays, you control the number of rows and columns and the distance between each. For polar arrays, you control the number of copies of the object and whether the copies are rotated. To create a multiple amount of the same object sometimes an array can be a lot faster than just simple copying.

So let’s start with Rectangular Array. At the end of this tutorial you will find an AutoCAD drawing file that you can download and use for this tutorial. As a bit of background our client has told us that he has two tables 210 x 50 units and 14 chairs, as represented in the drawing, that just happen to be 20 units wide and he wants them all facing in the same direction. He also wants them equally shared between the two tables.

Open the file you have downloaded………

We need to arrange the chairs in two rows, with seven chairs in each row. Here we go then, select the ARRAY icon from the MODIFY toolbar:  . A new window opens with all the pieces we need to array our chairs………

Before we go on with creating what our client wants, let’s take a closer look at this window to better understand it.

At the top of the window you can see that we have two ways to array Rectangular or Polar, as we have mentioned earlier, but we are interested in the Rectangular Array at this point only.

To the right of these commands is the Select Objects button, this, as it says, once selected will take you back to your drawing so that you can select your objects to array. Below this button the number of objects selected will be indicated. And below that again in the white box is a representation of your array, the darker of the objects is the original object.

Moving across to the raised box, we have ‘Rows’ and ‘Columns’ quantity boxes. At the moment they are in default mode and you can change these values to whatever you need as and when you need them.

Below these boxes is our Offset Distance and Direction section. Firstly there are three boxes where we can insert our own values for Row, Column and Angle. To the right of these boxes are buttons that we can use to select from our drawing precise distances or angles.

Then we have a tip area, which is only one tip anyway, and is a reminder for when you are entering values into your Row, Column and Angle boxes.

Finally to the bottom right of the window we have OK, Cancel, Preview and Help. These are self explanatory.

Let’s start drawing our array then. By default the window opens in the Rectangular Array mode, which, for now, is what we want. Now we need to choose the amount of Rows and Columns we want. Something to remember, Rows are horizontal and Columns are vertical. So for our chairs we want 2 Rows and 7 Columns. Type these values into the two boxes…………

So that you are not struggling for the moment the values for the offset boxes are as follows, Row offset 100, Column offset 30 and Angle of array is 0. Enter these values into the three boxes…….

All we need to do now is select the object we want to array, so select the Select objects button to the top right of the window. Then select the chair by clicking on it once………

A right click of your mouse button will then return you to the Array window…………

Notice now that all four buttons at the bottom right are now available. If you think that you are happy with all the values you have entered then just click OK, or click Preview to see if everything is OK, which is what we will do, so select the preview button………….

The little window that appears just asks two things Accept or Modify? Does the layout look OK? If it does select Accept, if it doesn’t then select Modify and return to the main Array window and change the values you have already entered. We think it looks OK so select Accept……….

That is the basic idea behind a Rectangular Array.

We can also create a Rectangular array along an angle……… let’s take our chair again and form a single row at a 10˚ angle to the original……..

Select the ARRAY button as before and enter in all the values as previous but instead of 2 Rows only have 1 Row and enter a value of 10 in the Angle of Array box………..

 

Here I am back again with another enthralling episode for you all………..

The Basics to AutoCAD

Part 13

Here we are again and another relatively simple tutorial this week. We are going to take a look at CHAMFER and FILLET. We have already come across these when we looked at polylines, but here we will take them as single entities.

So what does AutoCAD tell us about CHAMFER: A chamfer connects two objects with an angled line. It is usually used to represent a bevelled edge on a corner.

Let’s start with a simple 100 x 50 unit rectangle………..

Select the CHAMFER icon from the MODIFY toolbar; .

Firstly AutoCAD is telling us that the current chamfer distances are 0 and 0, these are the default settings when you open a new drawing. What we want to do is change those sizes.

On the actual command line AutoCAD is asking Polyline/Distances/Angle/Trim/Method/<Select an edge>: We are really only interested in two of these commands, polyline and distances. For this part of the tutorial we want to alter Distances.

So, in the command line type ‘D’ and enter, AutoCAD now asks us to specify the first chamfer distance, let’s say 10 for now, so type in 10 and enter. Now AutoCAD is asking for the second distance, so let’s make that 10 as well. Type in 10 and enter.

AutoCAD is now asking us to select the first line. So we need to know which corner of our rectangle we want to chamfer. Let’s do the top left corner. To chamfer that corner we need to select, first one of the two sides that form that corner, either the top 100 unit line or the left hand 50 unit line. It does not matter which at this stage so select one of those two lines.

Now AutoCAD is asking for the second line, depending on which of the two lines you selected before, now select the other one. And there you have it a chamfered corner that is 10 units in length from the original corner point………..fig A

Now with the same distances do the other three corners……. As you have already set the distance they will not need to be re-entered………..fig B

I have put the dimensions on so that you can see the principals of how this works. The original rectangle does not change size.

fig A

fig B

We are now going to alter this a little bit start with your 100 x 50 rectangle again, but this time the first distance will be 10 and the second distance 20 units. Now for the first line select the left hand 50 unit line and for the second line select the top 100 unit line. See how the chamfer is formed and try to understand how it has been produced, in as much as the first distance we supply AutoCAD will be the first line selected and so on……….

See how the chamfer in the bottom left hand corner is not symmetrical to the other three; this is because we chose the wrong line first.

Finally concerning CHAMFER you must take into account the actual length of the lines you are trying to alter. Just as a test draw the 100 x 50 rectangle and try chamfering a corner to these distances – 50 and 50. Now try 60 and 60.

Because you have selected a size larger than the actual length of one of the lines it cannot be chamfered.

Again if you have a drawing that you can practise on go ahead and see what you can chamfer and see if you can find any restrictions that might happen as you go…………

Ok then FILLET, what does AutoCAD say about this then: A fillet connects two objects with an arc that is tangent to the objects and has a specified radius. In layman’s terms it puts a rounded corner on our pointy corner.

Again let’s start with our 100 x 50 rectangle………..

Select the FILLET icon from the MODIFY toolbar: . Note that AutoCAD is telling us the current fillet radius is 0. This is represented in the command line by the figure in the brackets. Our command line is saying, Polyline/Radius<0>/Trim<Select an edge>: again we are only interested in the one command for now, the Radius command.

So let’s give our rounded corner a size, type ‘R’ and enter and then 10 and enter. This is telling AutoCAD that we want corners with a 10 unit Radius.

Now, as AutoCAD asks select the first object, or line. Then its adjoining line and hey presto a rounded corner appears. Do the same to all three other corners and you should end up with something like this………

Again I have put the dimensions on so you can see that the original rectangle does not change in size.

I must also point out that the same principal applies to fillets as it does with chamfers in as much as the size of your radius. If you select a size larger than the line you are using it will not work.

If you have a drawing you can practise on, again go ahead and have some practise. This time while you are messing around with the chamfers and fillets, try selecting some lines that cross each other. See what happens to them. But always remember to check what distances and radii you are trying to use.

Again, another short and sweet episode for you to ponder over.

The next two or three get a little bit more involved and a bit complicated so be warned…………

Here is the download for you     the-basics-to-autocad-pt-13