Extrusion in AutoDesk Inventor

This is just one hub in a series of 15 hubs on using AutoDesk Inventor for 3D modeling. The index hub is here.

Sketching is great, but it only goes so far. Extrusion takes that 2D sketch and turns it into a real live part. It's interesting to note that extrusion refers to both the computer process and the manufacturing process, and both do the exact same thing. So if you know one, you know the other. But extrusion in Inventor goes a bit beyond real extrusion with some of the functions, so it's still a good idea to keep reading.

In this tutorial, you'll learn how to extrude in a multitude of different ways. Sometimes I wish I could make up a use for some of these cool-looking shapes. Whether you're extruding with distance, "To Next" or extruding with "Cut." "Combine" or "Intersect," you'll soon be able to quickly make great looking parts.

Still have that sketch we made in the sketching tutorial? We'll be using that for this section as well. Just open the part it is in, and we'll get to work. Otherwise, make a sketch of your own - its not hard.

To start, click on the "Extrude" button in the "Model" tab. You'll get a menu that pops up, showing you a bunch of different options. It should look like Picture 1. We'll go through a few of these just to show you what Inventor can do with extrusion.

The first thing we'll try is the default: Distance extrusion. You can see that it is set to Distance under the "Extents" box in that window. Type in a distance, select your profile (I use the outer shape, not the inner shape) and watch the live preview.

The default gives us one direction, shown in Picture 2, but what if we want two? Check Picture 3. This shows us symmetric extrusion in both directions. You can change this by clicking the buttons under the distance box that show planes with arrows coming out of them.

Asymmetric extrusion lets us specify how far in each direction we want to go. In Picture 4, I've chosen 10 inches one way and 5 inches the other.

Now comes the interesting part. Instead of "Distance" as the extent, let's choose "To Next." You'll need another part for this, or you can just look at Picture 5. "To Next" extends the part until it hits a surface, creating a shape you could never have created with a simple distance extrusion.

Now let's mess with the "Join," "Cut," and "Intersect" options right in the middle of the menu. If you select Join, which is the default, the extrusion will become a normal addition to your part. That's what we've been doing all along.

Try "Cut." This is what I did in Picture 6. It takes the shape you drew, and carves it out of anything in the way for the entire distance you selected. This can be very handy for creating complex parts, since it is often easier to cut than it is to design that cutout into the part. Many times, it's actually the only way to get a certain shape.

When we select "Intersection," we get and even cooler part, shown in Picture 7. The intersection command deletes everything except where your extrusion and your second part come together, creating some really unique objects.

Go it all? Good! Extrusion is a key part of 3D modelling in Inventor, and you'll need to know it for just about anything you make. But believe it or not, there are even cooler functions coming up!