Join John Helfen for an in-depth discussion in this video Part feature introduction, part of Autodesk Inventor 2019 Essential Training.
- We're now to a point in this course where we can begin to talk about part features. These are the features that are used to created 3D models. We're going to take a moment before we dig into that to talk at a high level about how sketching and part modeling interact and the different types of features we have. In Inventor, we have the ability to create sketched features and placed features. And I'm going to go ahead and create a basic model and you don't need to follow along. You can just watch so that you understand the concepts and we'll dig into each as we move along in the course.
I'm going to start by creating a new part file and starting a new sketch. And I'm going to select a face to sketch on. Now, the first feature that you're going to create in Inventor for every single part is a sketched feature. What that means is that you have to draw a 2D shape that will define the 3D model that is created from that shape. In the browser you can see now, we have sketch one. I'm going to go ahead and right click and select 2 point rectangle and I'm going to select the center point of the sketch and just draw a rectangle.
I'm not going to put on dimensions or anything like that. I just want to show the process and explain the difference between sketched and placed features. I'm going to go ahead and finish this sketch and I'm going to right click and select extrude. By default, Inventor will select the close profile that we sketched and add a depth to it. Now, I'm going to go ahead and cancel this, just so I can show very briefly that that same shape could create other 3D shapes. If, when we right click, rather than selecting extrude, we selected revolve, Inventor will automatically select the single profile, but in this case, this 3D modeling feature has an additional input, and that's an axis.
If we select a line within this sketch, you can see that Inventor revolves around that axis point and we'd get a cylinder instead. That's really important so that you understand that each 2D shape could become a number of different 3D model shapes. I'm going to go ahead and right click and select extrude and accept that change, and start with a cube so that we can see the difference between sketched and placed features. In the browser, you can see our first sketched feature. This is called our base feature, extrusion one.
If we click the plus next to it, you can see the sketch that drives it. You can always go back and double click on the sketch to edit it. You can make it taller, you could add dimensions, you could make changes to it. But one you finish the sketch, the model updates. Next, we're going to go ahead and repeat that process. Once you have a base model, you're going to repeat the sketching and extrude or sketch and model process to add and remove material from this model to sculpt the final shape. I'm going to go ahead and select on this top face and I'm going to use the head's up display and I'm going to click the create sketch button on the far right.
This will create a new sketch on the top of that model and we can go ahead and right click and select center point circle to draw a circle on the top of this shape. The size doesn't really matter here. I'm going to go ahead and just draw the shape and finish this sketch. You can now see in the browser, we have sketch two. If we were to right click and select extrude, we can use that shape to generate geometry. I'm going to go ahead and shrink that down just a little bit and click the green check mark to select OK and create that extrusion.
Now in the browser, we have two extrusions. We can always double click on this sketch to go back and change the size or position of the circle. But, we're going to continue on and look at placed features now. Placed features are features that don't require a sketch, but instead require some piece of geometry from a solid model. The ones that are most commonly used are Fillet and Chamfer. Sometimes Hole is included there but it's unique in that you can create a hole using a sketch or placed feature.
It kind of runs the boundary between both. To create a fillet or round an edge, all you have to do is either launch the command from the ribbon bar under the modify panel and select an edge or if you select and edge in the model, Inventor head's up display automatically presents Fillet and Chamfer so that you can round or slice off this edge. I'm going to go ahead and click the Fillet command and you can use the head's up display to adjust the size of this fillet. Once you've got that created, you can click the green check mark to select OK and create that fillet.
The other option we had when we selected an edge was Chamfer. Chamfer is very similar to Fillet, except instead of rounding the edge, it simply slices the edge off. And it does it by default at an equal distance to each side. In this case, an eighth of an inch. There's other options here as well and we'll get into those as we get further into the course. But, if we click the green check mark, we now have a series of features in our browser that are both sketched and placed. The first two are sketched, since they are driven by these sketches that are consumed underneath them, and the last two are placed.
They don't have a plus symbol next to them because they're not generated or controlled by a sketch itself. Just like the sketches, you can always double click on these to return to that process and edit that feature. We could for example make this slightly deeper or slightly bigger, and click the green check mark and it updates. Let me go ahead and do that one more time. I'm going to double click on that fillet one more time because there is something else that happens here, that's important in relation to part modeling, and that's the fact that this chamfer is missing from the graphics right now and it's grayed out in the browser.
They way Inventor works, is it's a history based modeler. At the point in time when we created this fillet, the chamfer didn't exist. So essentially, when we double clicked on this fillet, we've gone back in time in this model, so that we can make a change to this feature and then when we click OK, Inventor traverses through the remaining features that may be below it and updates them according to this change. This is the power of a 3D parametric history based modeler. This give you a lot of logic and a lot of power in how you create this, and you can always go back in time to make modifications to what you've done already.
- The Inventor workflow
- Drawing lines, shapes, and splines
- Modifying sketch geometry
- Creating work planes, axes, and points
- Projecting and importing geometry
- Modeling parts
- Building parts with placed features
- Creating patterns
- Creating sculpted objects
- Adding parts to an assembly
- Using constraints to position parts
- Enhancing designs with visualization techniques
- Creating drawing views
- Creating basic annotations