Now that we have gone through a few commands, let us use them in a practical sketch.
This sketch is a basic sketch that will give us an idea about using a few of the commands and how to use them with each other making a sketch with dimensions and constraints. They’re also the introduction to modify commands which are an essential part of sketching and modelling in AutoCAD.
First, we make the circles, even though we see the few arcs in the sketch its always better to go for the easier and faster option, and we can make the circles and cut them which is better for now.
Always see the part of the sketch which has exact dimensions given and we can start with it as the backbone of the sketch. Here we can see the distance between the centers of the circles, which is where we start.
We notice that the circles do not stay in place when giving them a certain distance from the parametric tab.
The parametric tab is used to give dimensions and constraints to the sketch which is always vital in AutoCAD. We use the Concentric command which makes the circle have the same center to fix the circles’ position.
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Now that we have made the circles, we go for the lines. We can see the lines are tangent to the circles, go to line command, press Shift+RightMouseButton go to tangent. Select the circle to which the line has to be tangent, hover the mouse over the circle to bring out the center, now from that center find the intersecting point by simply moving the mouse upwards on the green line. Click the point and add dimension as shown.
Make the second line similarly, except finding the endpoint by hovering over the end of the previous line and going down to make it horizontal to that distance. There is not a certain dimension given for this but we know it goes there from the sketch.
Now, a Fillet has to be made, this command comes from the modify tab to make rounded corners from sharp corners. Go to fillet, select the first line, now press ‘r’, press enter, then enter the dimension that is 10 here, press enter again, now select the second line to make a fillet with 10mm as the radius. (We will ignore the 15mm radius given on the sketch as its 10 only)
We are going to use the trim command now, to trim the excess parts that we do not need. We are also going to leave one half of the sketch so as to mirror the other half to avoid making the same thing again.
Click on trim or type ‘tr’, click on the section about which we need to trim and press enter. Now select the lines and parts that we do not need one by one and press enter. Repeat the process for vertical sections that we do not need. Then erase the parting line that we made.
We now use the mirror command to make the same sketch from a parting line that we are going to define. We do not necessarily need to use the mirror command as there are only some parts to make, but this is something that we are going to do in future sketches as things get more complex, we always have to save time and make only one half. Most of the time there is symmetry in the model and mirror command is a useful function for all this.
Find the mirror command in the modify tab, or just type MIRROR. Select all of the sketches by clicking the mouse once and the moving towards the other end and click again. Now we define the symmetry line by selecting the first and endpoints of the sketch.
There is an option for removing the other half we click on NO to that and press Enter.
After mirroring, you will notice that when we select parts of the sketch, they are divided and only half is selected at once. We use join command to join both these halves.
Click on join from the modified drop-down arrow, or just type join in the command line. Select the whole sketch as shown and press enter. The sketch is a whole now and upper and lower halves are selected as one.