When I first started to learn CAD a few years back, I had a major problem with my learning process. I couldn’t find any exercise material. I searched and searched but couldn’t find anything useful. I decided to create the 101 CAD Exercises book to help others speed up their learning process and make it more hands-on and fun. If you want more exercises like this, you can get them here. (The exercises are 2D and 3D drawings without instructions so that they are not specific to AutoCAD.)
In this tutorial, you will learn how to create a piston using 3D geometry in AutoCAD. To do this you will use the 2D drafting and annotations and the 3D features. I assume that you are already a bit familiar with the basic 2D drawing commands such as LINE, CIRCLE, TRIM, etc. The final model should look something like this in 3D.
Here are the 2D drawings:
Remember that using gridmode (F9) and snapmode (F7) can be helpful between drawing tasks. For this exercise, I’ve been using AutoCAD 2017 but it will work with previous versions as well as other CAD software. Your commands and shortcuts might differ with other versions, though. The dimensions that are used in this exercise are originally metric but since it’s all proportional you can use the same values but with imperial units instead. I’ve decided to keep the measurements unitless for this exact reason.
Start a new drawing in AutoCAD.
Draw a circle with a diameter of 60 and place its center on the origin (0,0).
Draw a horizontal line that starts at the origin and a length of 23. This line will be used as a reference length for the next step.
Draw a rectangle using the RECTANG command as shown on the right side of the image below, using the endpoint of the line as a guide to place the rectangle. The dimensions of the rectangle don’t need to be exact but they must exceed the circle perimeter as we use it as a cutter. Then mirror the rectangle using the start point of the line (or the center of the circle) for the mirror line. Remember to erase the reference line that you used to create the rectangle.
Now draw a concentric smaller circle with a diameter of 52. Also, draw a vertical line 19 units to the right of the center of the circles as shown below and mirror it. As with the rectangles, the lines need to exceed the circle perimeter.
Now use the TRIM command and use the vertical lines as edges to trim the inner circle. Resize the 2 vertical lines so that they end at the top and bottom arcs. Then use the JOIN command to make the following shape in the center.
Click the gear (Workspace Switching) icon on the bottom right of the screen and choose 3D Basics instead of Drafting and Annotation. Also choose a 3D viewpoint so you aren’t looking at plan view.
Now use the EXTRUDE command to extrude the shapes to make a 3D model. The Z dimensions (shown below) are 40 units for the rectangles, 44 units for the central shape, and100 units for the circle. This image is using the X-ray visual style.
Now start the SUBTRACT command and subtract every shape from the main cylinder. Remember that first you must select the main cylinder, press Enter and then select the objects you want to subtract from it. You might need to change your viewpoint or visual style, especially to subtract the central shape. Now you should have a model looking like this:
Now you should go back to the 2D Drawing and Annotation and return to a top 3D view such as SE Isometric if necessary. Drawa concentric circle with a diameter of 52 and a rectangle (using the RECTANG command) with a height of 7.5 and one of its sides on the x-axis as shown in the image. The length of the rectangle should exceed the cylinder diameter, which is 60.
You can isolate (hide) the main body by right-clicking on it and choosing Hide or Isolate>Hide. Then use the COPY command to create two more circles, 44 units and 100 units in the z-direction. After this, delete the base circle. Go back to the 3D Basics workspace.
Use the EXTRUDE command on the 2 circles; the lower circle should be 42 units upwards and the circle on top should be 10 units downwards. Then use the REVOLVE command on the rectangle to make another cylinder. Specify the X axis as the axis of revolution and use the default 360° revolution.
Now right-click and end object isolation (Unhide). Using the MOVE command, bring the thin cylinder 20 units upwards in the Z-direction and move it towards the main body of the piston so that it extends on both sides.
Now subtract the 3 cyllinders from the main body. You can use the Bottom view for easier access.
In the 2D Drawing & Annotations workspace, draw a concentric circle with a diameter of 20 units. Use the EXTRUDE command to create a cylinder that is higher than the main body. Then subtract it from the main body.
Now use the CHAMFEREDGEcommand pick the outer edge of the top face of the cylinder, press Enter and type d to give it a distance from the edge. Choose 1 unit as the distance and then press Enter. You must enter the distance twice to give it the same distance from both edges.
Start the FILLETEDGE command and then pick the inner edge of the top face of the cylinder, press Enter, and type r to give the fillet a radius. Choose 1 unit as the radius and press Enter.
Next task is to fillet the side faces. Use the same command as in the previous step.
We will now create the ring pockets on the piston’s outer wall. Use the TORUS command. Set the center of the torus to the origin (0,0) and then use 60 units as the diameter and 3 units as the thickness. Make three copies of the torus (using the COPY command) with the following values in the z-direction: 76, 83 and 90 units.
You should delete the first torus. Remember that you can isolate (hide) the main body for this step.
Finally, subtract the tori (plural of torus) from the main body. You should now have a 3D model that looks like the one at the beginning of this post.
Are your drawings bloated for no obvious reason? When you insert a block, is there a long list of blocks that aren’t in the drawing? Ditto for layers?
Oversized drawings load more slowly, take up more storage space, and take longer to save.
Then you need the PURGE command!
Yes, you want slim drawings
Definitions of blocks, layers, styles, and more that aren’t actually used in the drawing make it slow and cumbersome. The PURGE command finds named components that aren’t used and lets you delete them. In a complicated drawing, there can be dozens or even hundreds of unused layers, blocks, text styles, dimension styles, and more.
To start the PURGE command, choose Application Button, Drawing Utilities, Purge or just type purge on the command line. The Purge dialog box opens. Components that have unused items have a plus sign next to them. In this figure, you can see that there are unused blocks, dimension styles, layers, and linetypes. You can expand these items to see what you can purge.
This is a guest blog post by Jaiprakash Pandey, who is a CAD Corporate Trainer specializing in AutoCAD, CATIA and other CAD software’s. He is an Autodesk AutoCAD Certified professional and an Autodesk expert elite. He is a regular contributor to AUGI World magazine and he has also developed AutoCAD video courses for pluralsight, his own platform SourceCAD, and other E-Learning businesses. Explore more AutoCAD tutorials on his blog, SourceCAD.
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With AutoCAD, you can create a short animated walkthrough video of your architectural model that can help you in presenting your ideas in a more creative way. Using short animated walkthroughs you can simply convey a lot of information without using many tools or drawings and even a non-technical person will be able to understand your design ideas.
This is a guest post by Khwaja Ibrahim. He is a Mechanical Engineer by profession and a CAD Engineer from Pakistan. His services range from designing for 3D Printing, Sheet Metal, Injection Molding and Manufacturing processes to providing Photo-Realistic Rendered Images.
He gets the utmost satisfaction in bringing ideas to life allowing him to demonstrate his creativity, designing and imaginative skills. As you can see, he also writes tutorials. This one is from 12CAD.com
By default design, AutoCAD’s line is a single entity. This singularity of the line allows it to be treated as a simple drawing element without the leverage of more complex types. However, for those of you who may require such a feature, there is a way other than grouping different colored lines into one.
As said, by default the line is a simple element hence to replicate functionality not built-in, we need to setup the proper environment before we proceed with the actual development. See the below screenshots for a step by step explanation of the prerequisites of sawing multicolored lines.
Step 1: Command: MLSTYLE. Use the command MLSTYLE to access the Multi-Style menu. When you press enter, the dialogue box should open up.
Step 2: View current profiles
By default a “Standard” profile is defined for regular line drawing. This is also set to the current profile in selection. At any time, this one profile will be available if there are no other. Create a new profile as shown below.Step 3: Create a new Multi-Style profileContinue reading How to create multicolored lines in AutoCAD
AutoCAD 2011 introduced the transparency property for objects. Transparency gives you the opportunity to create presentation-ready drawings. You can draw an object that is up to 90% transparent. Here you see some trees filled with a 60%-transparent solid fill.
As with other object properties, you should use the Layer Properties Manager to create a layer and specify the transparency as a layer property. Here you see a red layer that is 75% transparent.
Transparency is pretty useless for the line that delineates an object, but is quite useful for a solid fill hatch or a gradient. Here you see the effect of a red 75%-transparent layer on top of an opaque blue layer. The result is purple at the point of overlap.
To create an object with a partially transparent solid fill, follow these steps:
Open the Layer Properties Manager (the LAYER command).
Click the New Layer button and name the layer.
In the Color column for that layer, click the color swatch and choose a color.
Click in the Transparency column for that layer to open the Layer Transparency dialog box and type a value between 0 (completely opaque, the default) and 90 (mostly transparent). Then click OK.
Make any other changes that you want to the layer’s specifications and close or collapse the Layer Properties Manager.
From the Home tab> Layers panel< Layer drop-down list, choose the new layer to make it current. (You can also do this after the next step.)
Draw a closed object.
Choose Home tab> Draw panel> Hatch.
In the Pattern panel, choose Solid.
At the Pick internal point or [Select objects/seTtings]: prompt, pick inside your closed object.
Press Enter to accept the solid fill and end the command.
Do you use transparency in your drawings? Why or why not?
This is a guest post by AutoCAD expert Edwin Prakoso. You can find this and other AutoCAD tips on his website here.Edwin Prakoso works as an Application Engineer in Jakarta, Indonesia. He’s been using AutoCAD since R14 and Revit since Revit Building 9. He occasionally writes for AUGIWorld magazine and is also active in the Autodesk discussion forum. He’s an Autodesk Expert Elite, certified as Revit Architecture 2014 and an AutoCAD 2014 certified professional.
One common question that I get is how to access AutoCAD commands quickly.
AutoCAD is 30-year-old software. People used it before it ran on Windows. It was designed to run on different operating systems and different standard interfaces that are used today. That’s why there are many methods to access AutoCAD commands. One method may be faster in general, but another method can be faster when doing other tasks.
For example the command line is faster for most AutoCAD users for activating a line command. But Function keys are faster to toggle Ortho mode. It would be better for you to know all methods, so you can decide which one works best for you.
So let’s explore all the methods that you can use to execute AutoCAD commands and see how you can use them effectively.
The ribbon was introduced in AutoCAD 2009. If you learn AutoCAD after this version, you probably use this as primary method. I found that many occasional users also like ribbon.
Many AutoCAD veterans don’t like ribbon, because it’s a big change from toolbar to ribbon. It feels slow (personally I feel it becomes better in later version) and take too much screen real estate.
This is the most apparent way to activate a command in latest version. Even if you’ve never seen AutoCAD in your entire life, you know you can activate a command from here.
This is a fairly simple wheel with a center tube for an axle/pole, a rim, and 6 holes. You can create a 3D wheel like this entirely with cylinders! Watch this 9-minute video tutorial and follow along to create it from scratch yourself.
You’ll learn how to:
Create cylinders: Cylinders are an obvious choice for a wheel and are often used in mechanical drawings.
Set the workspace to 3D Modeling: The 3D Modeling workspace gives you all the tools you need for 3D work; you won’t find them in the default workspace
Use the SUBTRACT and UNION commands: These are called Boolean commands and they let you carve out holes and combine objects
Change the visual style to check your work: The default wireframe makes some work easier, but it’s really hard to tell if you made mistakes. This image uses the Conceptual visual style, which makes everything very clear.
and a few more tasks.
The basic concepts are applicable to many types of 3D models.
Here’s the video. Let me know in the comments what you think! Do you have suggestions for drawing this differently? Did you run into problems? And use the Share buttons below the post to share with your colleagues so they can practice it, too!
If you have LOTS of drawings and want an easier way to find them, you can give them properties that you can search for using Windows Explorer. You can even create custom properties. You’re supposed to be able to search for these properties in the Design Center and Content Explorer, but neither one worked for me. Of course, you can search for drawings by name, but what if you don’t know the name? What if you don’t know when it was last modified? Drawing properties can help.
Create the drawing properties
To specify drawing properties, choose Application Button, Drawing Utilities, Drawing Properties. This opens the Properties dialog box. It has 4 tabs:
General: This is just for your information. You can’t add properties here.
Summary: Lets you specify a title, subject, author and add keywords. You can separate multiple keywords with a comma. You can also add comments and a hyperlink base to use for relative hyperlinks.
Statistics: This is also for information only and tells you when the drawing was created and last modified, who last saved the drawing, the revision number (if any), and the total editing time.
Custom: To add custom properties, click the Add button. Then type the custom property name and value and click OK.
Of course, you want to use properties that will help you find the drawing. You might add properties for clients, discipline (architectural, mechanical), geographical location, etc.
Search for a drawing by its properties
To find a drawing by its properties, open Windows Explorer. Then follow these steps:
In the left pane, click where you want to search. It can be a drive or a folder.
Type a search term in the search box at the upper right. I searched for “chapter,” which was my property. I didn’t have to know its value.
At the top, choose Advanced Options and check File Options.
That found the drawing that contained a custom “chapter” property, as you can see in the figure below.
Why not Content Explorer or Design Center?
I tried searching in the Content Explorer and the Design Center and came up empty. What is your experience using drawing properties? If you don’t use them, would they help you? Leave a comment. And please share this post using the Share buttons below — maybe someone else will find it useful.
First set the layer that you want to use for your solid fill. The hatch will go on the current layer.
On the Home tab in the Draw panel, click Hatch. The Hatch Creation tab appears.
In the Pattern panel, choose Solid.
If you have one closed area, you can just click inside it to pick an internal point. If you want to select an object, you can click Select in the Boundaries panel, as you see here. Then press Enter to end selection.
Press Enter to end the HATCH command.
Turn fills on and off
I thought I’d tell you about the FILL command. This command (which controls the FILLMODE system variable) can show or hide solid fills. Its original purpose was to help your computer run faster if you had lots of solid fills. Nowadays, that isn’t usually a problem, but turning off solid fills can sometimes help you see your objects more clearly.
Just type fill and press Enter. Then choose On or Off. Type regen to see the change.
Warning! If you turn off fills, they don’t plot! So be sure to turn them back on if you turned them off for ease of editing.
The SOLID command that isn’t a solid
The SOLID command is an old command that’s rarely used now because using the Solid pattern of the HATCH command is much easier. It was the original way to fill a closed area with a solid fill, hence the word “solid.” It’s not related to 3D solids, although if you create an object with the SOLID command and give it thickness, it creates surfaces with tops and bottoms.
You can only use SOLID for straight-edged objects. First create the object and turn on object snap for endpoints and whatever else you’ll need. Type solid and press Enter. then start specifying points in a zigzag fashion. After the 4th point, you’ll get prompts for the 3rd and 4th points over and over until you’re done. You continue to create adjacent triangles in this way until the shape is solidly filled. Press Enter to end the command.
If you found this post useful, please use the Share buttons below so that others can learn as well!