In this lesson we'll create a recess to hold a hex nut. After completing this lesson, you'll be able to create a mirror feature, use sketch polygon. So, at this point, we have cable entries and exits from our component tray, we have the holes where we can actually bolt this to the airframe or the Xstar body. The last thing that we really need to take care of is cutting the hexes. Now, this is a fairly straightforward process. We're going to create a sketch on the top plane, so we're going to go the origin, the XZ plane, create a sketch. Now, we have the bolthole locations, but I'm going to use P on the keyboard and I'm going to project these. And we really only need to cut one because we can mirror them, but I'm going to go ahead project all four of those. Go to sketch. We're going to be using a polygon, and you also have the option to right click, go down to sketch here, go to polygon, and use a circumscribed polygon. And we'll go to the center point of this hole. And notice it's not snapping to it, but that's okay, I'm going to place it here anyways. I'm going to give it an eight millimeter diameter. And notice that that actually gives it an eight millimeter radius. So we're going to put a four. We're going to go back to our sketches folder. We're going to go to our folder for the component tray location. And we're going to bring this down, and we're going to snap it to this whole location. We're going to make this horizontal. Now, we have enough material here for an eight millimeter nut. Now, if you want to, you can dimension this after the fact. When you're placing it, you don't have to add the dimension, and then it will be under constrained. We can add a dimension from here to here, of eight millimeters. And now we have enough material here for an eight millimeter nut. Now, I think it's a good idea to add a little bit because this is geometry that's very hard for you to modify after the fact. So I like to go at least a quarter or a half millimeter larger, to make sure that I have enough room to drop that in. I'm going to stop the sketch. I'm going to create and extrude using that profile. I'm going to hold down the left mouse button, and it's like that as well as the inside. And what I want to do is I want to make sure that, when I extrude this I have a flat face that I'm extruding from. So in order to do that, I have to do an offset plane, and I'm going to offset this 70 millimeters, and pull this up and see where this gets me to. So as I look at it from the front, I want to make sure that I'm not leaving too little amount of material here. So I might actually want to go up 71 millimeters, and say okay. Now the thickness of the nut is going to depend on what kinds of nuts that you order. In our case, it's two point seven millimeters tall, and if you remember, the cut down that we used was three millimeters from the top. So it looks like we have plenty of material here and we can actually measure that to make sure that we do. If we measure this edge, the height of it is three point four seven millimeters, that's plenty of material here to drop the two point seven nut in there. So let's go back, let's hide all the old sketches, and let's create a mirror feature of this before we save. So under create, we're going to mirror, feature. We're going to mirror this across the front plane. We're going to say okay. Then we're going to repeat that command, and we want to mirror the original, as well as the mirror. And we're going to take these across the right plane, and again say okay. So now we have the hex nut cut outs on all four bolt hole locations. We can drop an eight millimeter from flat to flat, that's for a five millimeter screw, and we have the counterbore to use a socket head cap screw. It's five millimeters. We can zip tie our batteries on. We have all the different component holding locations on the inside. So let's go ahead and save this file, so we can move on to the next steps.