Lecture 5

PROFESSOR: Welcome to Lesson 5. Today we want to spend just a few minutes, this will be a short lecture, but a few minutes reviewing some of the tools that you will need to complete the four drawings assigned for this lesson. I want to remind you about how to do Fill it, first of all. That's going to be necessary in the T plate design. So let me start with, I'm using POLAR to simply make a 90-degree angle with 5-unit long lines. If you needed to do Zoom Extents before you got started to make sure that your 5-inch long line is appropriately spaced for the size of the screen, then do that. You can always Zoom Extents afterwards as well. But what I want to do is demonstrate and make sure you see the Fill it command and how to use this carefully. Now, if you have Dynamics turned on, then you will need to, or you can, use the pull-down menu here. See the little arrow pointing downward? I'm just going to drop this down and select the radius, because I need to define what the radius curve will be. I want to make a radius curve of 2.5 this time, a very large Fill it radius. So I'll just have to select the two objects, the first and the second. And it's very large for this size. If I'm designing a highway, I might use a 50-foot radius or a 200-foot radius if it's a high-speed highway. Various sizes would be appropriate. But let's undo this and just go through it one more time, this time without the dynamic input. So if I want to do a Fill it radius on the command line here, I would have to say r for radius and then define the Fill it radius. Let's go with a 0.5 this time. And then it doesn't matter which one is first and which one is second, but define the two points. OK. Once I have this ready-- let's go ahead and undo it again. And I'll make the third leg of this object for the demonstration. Remember, using POLAR I can just simply enter the distance that I wish. And it will go that far in the direction that I'm pointing. So Fill it radius, let's go with the most recent one that is recorded here, is the Fill it radius of 1. But if I want to change it one last time just to demonstrate, let's make it a 0.75-inch Fill it radius between these two objects. Repeat the last command by saying right-click and Repeat or just simply Enter on your keyboard. OK. So now I have this. What I would need to do also in this case would be, and to prepare you for the T plate design, is establish a center line. So I'm going to make this five units as well, notice on the command line. OK. So I have a center line representation here. Let me select this and go into my line type control and apply Center. Now, if you weren't sure how to get that, we can always go to Other, load from the library all the available lines. And if you scroll down through the list, notice there is a basic center. There's a half-size and a double-size. And as we learned already, there are a number of additional line types already loaded and available for you. But if we had decided that we needed something different, this would be a place to go and shop. So let's go ahead and stay with the center line for this. And OK. It's already there in my case. And then I can simply select the line and apply it. OK. So I have a long short line type called Center. And that will represent the midpoint fold line of this object. The next example that I need to go through with you to help make sure you're ready to draw the gasket, actually there are two gaskets for this assignment this week. And I need to remind you or show you something new that will be most helpful for you in this case. The best way to do this is probably to take you through a portion of the drawing and let you do the rest on your own. So this will be a little bit more guidance through the project. But stay with me here as we work through the first gasket in your assignment for the week. Notice that there are four corner circles that will sort of be anchors in this project. And they each have a defined radius. So if I'm going to use the circle and it's asking me to define the radius-- let me go ahead and select circle command again. OK. And I'm going to use dynamics this time. So asking for a center point. It doesn't matter where in this case. I'm going to go ahead and select here. Then it asks me to define the radius, which is 0.5 units. OK. And then I can use a copy command with POLAR to grab the center point and move this circle to the next position, which if you're looking at the description, it's 3 units away. Another one is going to be a full 2 units away. And then I need to escape and do another copy from center point over 3 units. OK. So I have the four anchors. Now if you'll read the instructions carefully for this, and I do want you to spend the time thinking this through, there are additional circles on the inside of each of these. And they have a diameter of 0.5. That phi symbol is a diameter. So let's say I can choose d for diameter. And then I'll say 0.5 here. So that will be a smaller circle on the inside. Let's go ahead and copy this the four times to establish the corners of this drawing. Finding the midpoint is helpful by using OSNAP. And then once again I'll copy this one from center to center. OK. Now, the part that you will need some help on, this part will be easy to connect across the top if your OSNAP settings are set correctly. What I want is a quadrant and a node. We use both. But a quadrant would allow me to select from here to here. OK. I could do that exact same thing again, going from here to here. All right. So the question now becomes, how can I make the curve to go from here to here? That's required. It's a specified curve, radius curve, of 3 units, 3 inches. So let me move this up into the center of my screen and make it a little larger. Now this is the part you may not know if you haven't played with this before much. Circle command and then specify the center of the circle. Or I could use a command here called Tan Tan Radius. Let me get back to the drop-down menu so you can see it more clearly. But I'm going to select TTR. OK. Now it says to specify the point or specify point on the object for the first tangent. Well, I'm going to just hover around here. It's going to be touching this circle at this point and this circle at this point. Then it asks me to define the radius. Well, my radius will be a 3. OK. So it has found the one and only tangent point of that circle. The graphics may not be clear enough to see that it is indeed touching, but it is. So let's go ahead and follow the next step, which would be to trim. So the next step is to select the cutting edge. And I should point out to you that if your display line is very reduced, like this, you may not be able to read all of the information. So be sure to raise up your command line enough to read the instructions at the bottom of the page. All right. Back to this object. It said I needed to select my cutting edge. Well, the cutting edge will actually be this circle and again this circle. Once I've selected, I'm going to press Enter. And somewhere on this side of the circle, it could be anywhere from here all the way around, I can trim. So now I have the one and only connecting tangent point on the left side. Maybe it would be worth it to do that again, just for the practice. Let's do a circle on the right side. I'll use the dynamic input, pull this down to Tan Tan Radius, select the approximate area here and here. And it's really the quadrant, so somewhere in that quadrant with a radius of 3, I plan to have a large circle connect. And then trim. So against this and this, Enter. And I want to cut here. OK. Great. Now there is also a Tan Tan Radius on the inside. I'll do one for you and let you finish this drawing by trimming properly. I'll give you one more little hint. OK. So in this case, I'm going to have-- I may need to turn off my OSNAP if this is a problem. But in this case, once I select Tan Tan Radius, it will automatically populate the Tangent icon here even if I don't have a selected on my OSNAP positions. And the radius of the smaller circle was given as a 0.56. OK. And then the last time, we'll trim. Let's go here. And I'm going to select both of these objects as my trims and this side as the cutaway. All right. So to complete this portion of it, you can do some trimming with boxes that way, like I did a moment ago. I want to use these two objects as my trim edges, the cut edges. And then select both this and this as the cutaway. OK. So there's some more work for you to do. And I will leave it for you. One thing you could do is offset from the top row down the distance, which is going to be calling for a 0.75 distance. And then you can continue trimming and continue completing this drawing, this gasket. So good luck with this project. I hope it goes well.