In the last lesson we created 3 separate pieces within a single part file, and I mentioned that we created 3 solid bodies. I just want to take a minute to clarify the difference between solid bodies and features with multiple separate pieces.
This is actually a single feature with 3 separate pieces, not 3 solid bodies. If you expand the Solid Bodies folder you can see that there is only one solid body named Solid1. If you expand Solid1 you can see Extrusion-1, and beneath that is Sketch-1.
One method of creating assemblies is to create all the parts in a single part file, and then you separate them into an assembly file. This process is covered in detail in the Assemblies and Advanced Concepts course, so for now I just want you to be able to identify the number of solid bodies in the file. So we’ll need to create a second body, and before we do I want to change a couple of settings in the Application Options.
Expand the Tools tab, and then open the Application Option. Now expand the Sheet tab. As you’ll see in just a minute you can automatically project the edges of a face onto the sketch when you create it, and in order to do this, you need to have this option checked. Auto-project edges for Sketch Creation and Edit projects the edges of a face onto the sketch when you create it. Select it, and then I’ll show you how it works. Click OK, and then open the 2D Sketch command. Now select a face on the extrusion. As you can see, Inventor has projected the edges of the face onto the sketch to create a closed profile. So now we don’t have to draw it.
Finish the sketch, and then open the Extrude command. If you recall, the Extrude command can Join, Cut, Intersect, or make a New Solid. If you want to make a new body you have to select New Solid. Select this option, and then apply the command. Now if you look in the Solid Bodies folder you can see that there are 2 solid bodies in the folder, and the number 2 indicates that there are 2 bodies.
The Solid Modeling course covers single body parts, and as I said, the Assemblies and Advanced Concepts course covers multi-body parts, but I also know I’ve probably sparked your interest in working with solid bodies. So I’ll give you a little more information.
One thing you might be wondering is if you apply a join operation to the part, which body is the feature added to? The answer is this. If you select a surface on a body to create a sketch, the sketch is a child of that body. So the feature created from the sketch will be a member of the same body. In other words, if I select this surface to create a sketch, the surface is part of Solid2. So the feature created from the sketch will be part of Solid2. If I select this surface to create a sketch, the feature created from the sketch will be part of Solid1. You might try this with this file before you proceed to the next lesson, and as I said, it’s covered in detail in the Assemblies and Advanced Concepts course, so there’s no need to master solid bodies at this time.