In this lesson, we'll start creating solids for a quadcopter. After completing this lesson, you'll be able to, create an extrude surface, create an offset surface, and create an extruded solid. Now that we've done the work to create our layout sketches, let's get started by creating some geometry. If you want, you can upload the X Star V five file, or you can carry on with your file. We're going to navigate to the ''patch'' work space, we're going to make sure that our X Star component is active, and I'm going to rotate this slightly forward. We're going to be using the front profile sketch, and we want to create and extrude. So we're going to take this sketch and we're going to pull it forward, and then we want to change the direction to be symmetric. When we look at it from the top, we simply want to make sure that we extend past any geometry we need. We're going to be cutting this outside area here, so we just need to make sure that we extend past that. 200 millimeters should take care of it. Next, let's go ahead and select create an offset, and we're going to take this upper surface and we're going to offset it in minus eight millimeters. This is going to represent the top and bottom of our solid geometry. Next, let's hide our top down cut and show our top down shape. We're going to extrude this as a solid, so we need to go back to the model work space and create an extrude. We're going to select both of these areas. In the start is going to be from object, and we'll simply select the bottom surface. In the distance will be to object, and we'll select the top surface. We're going to be creating a new body inside of our component, and say okay. In the ''bodies folder'' we can now hide body one and body two, and take a look at the result. So, what we've created is a solid representation of the right half or part of our shape. So, if we look at it from the top, it has the X shape, and remember that we modeled in all the symmetry. So everything from here is symmetric. Now, if you're not completely new to CAD or Fusion 360 you might be thinking to yourself, ''Why didn't we just do a thicken?'' We can trim the surface, we can create a thicken, and use that solid geometry. That is perfectly acceptable, but the main reason I did not use the thicken is because I wanted all these side walls to be vertical. So, if we look at it from the top, we can see the top and bottom edge right here. Now, if we were to do a thicken, what would happen is you would go out, normal to the direction of curvature. So from the front it would be okay on a mirror plane, because we had tangency here and it would go straight down. But everything as we get over to the edge would come down at an angle. Now, again, that's okay. It really doesn't matter for a 3D printed part, as opposed to something like a machined part. But in general, doing this method where we have a straight extrude without tapered walls makes the rest of our modeling a little bit easier. Now, Fusion is really great about recovering documents, but I always make it a point to save often. This always gives me a version that I can go back to and promote at any point in time. So now that we have the basic shape, we want to use our top down cut and we want to remove some material. So again, we're going to do an extrude, and this time we need to select the areas that we want to remove. So, we're going to go through, we're going to select all the areas that we want to get rid of. Now, we do have to be careful here, because some areas we do want to keep. So, as we look at this, these areas here are going to be structural and we have to decide if we're going to keep them or if we're going to remove them. So, right now, I'm going to actually deselect them and I want to keep them. But notice that we need to select the small area in here, on both of these, because that was a projected edge. If we look at it from the top it might make a little bit more sense. So, we drew this larger circle and we based its dimension off of the actual outer diameter of the prop. So, to make sure that we have symmetry front and rear, we needed to select that small segment. Let's go and rotate this around, and let's extrude this up until we cut through our shape, and we get a preview on screen of how this looks, and we can say okay. So, now we've removed material from the top shape and you can see that we've actually left some small pieces in here. So, I want to go back, I want to modify this, and I want to remove those as well. So I'm going to take out just that small piece so I have a nice square edge, and I'll come over here and do that as well, take out that small piece, and I can say OK. So, now I have that nice square cut. So I'm going to go to a top view, fit the screen and take a look at what I've done. Let's go ahead and temporarily show the top down cut sketch. Now, notice that we had this brace in the middle, so there are a few things that we need to think about here. We know that we want to have a small wall in this section for structure. But we also want to make sure that we reduce the thickness in that area. So we can either decide to have that added in now and remove it later, or we can remove it now and add it back later. Because we already know how to remove, I'm going to go ahead and remove it now an add it back later, so that we can explore some other functionality. So, what I want to do is, I want to rotate this around and I'm going to be taking out these areas as well. So now if we OK, we fit to screen and then get a top view, you can see that we've removed those extra areas, and we're going to go back at a later point in time and we're going to add them back in for some additional structure. But I do always have this top down cut reference sketch that will help me figure out where that material needs to be added, at some later point in time. We also want to go ahead and rename these surfaces, as well. So I'm going to call this one ''body top'', and I'm going to call this one ''body bottom''. So at any point in time, if I want to add some additional extrudes I can always come back knowing that these walls are completely vertical. I can add an extrude going from the top surface to the bottom surface, or vice versa. And that way I know that I'm ending at those same extends. So again, as always, save often to make sure that you're not losing any of your work. So, we're just going to hit save one more time, so that way we can move on to our next step.