39-245
Rapid Design through Virtual and Physical Prototyping

IronCAD Lab - Two

Before starting the lab, copy fanhousing.ics to your desktop. You can either navigate to the rapidproto/labs folderfrom your personal link to the class afs space, or you can open your browser to http://www.cs.cmu.edu/~rapidproto/labs/IronCAD to get a listing of all the files in the IronCAD folder. Right click on fanhousing.ics and save it to your desktop. Use this copy of the fanhousing because we shouldn't have blended the edges in the previous lab.

In this directory, you will also see some help files in pdf format that I have created for you to use when you are creating your CAD toy conecpts. These help pages are linked in the main listing of course pages too

1. Using the triball

Now click on the triball icon:

1.1 Locking an axis

1.2 Moving a part

Move the cursor until you have a hand with the right and left pointing arrow under it.

If you move the cursor, the part will move up and down along the z axis, but it will not move from side to side.

Now, move the cursor until you have the mitten hand with the circular arrow under it.

As you move the cursor, the part will rotate around the locked axis.

Notice that as soon as you click on another handle (or anywhere else in the scene), the axis unlocks.

You can move a part more precisely by right clicking on the triball handle for the locked axis.

When you select Edit Distance, you will get a dialog box that lets you enter a number for distance.

What distance is this? This is the distance you want to move the origin of the triball along the axis of the selected handle. If you press OK in the dialog box above, the block will move up three units in the z direction. Try some different values. Remember the Fit to Screen button will get your part back in view.

1.3 Relative positions and orientations

Drag a cylinder into your scene. Be sure it is separate from the block. That is, be sure that none of the points on the block is highlighted when you drop the cylinder into the scene. Notice that as you drag your cursor over the screen, that IronCAD displays the coordinates for the anchor of the cylinder.

Notice the thin green lines in the screen dump above. As you move the mouse around, you should see the coordinates change. If I drop the cylinder there, it will be on the x-z plane, not the x-y plane:

If you selected a scene with the x-y-z plane datum, as you drag your part around the scene, you can tell which plane your part will drop on depending on which plane is currently highlighted in green. Drop the cylinder somewhere on the x-y plane apart from the block.

Now, resize the cylinder using the IntelliShape handles to make it tall and thin.

Reminder: To get the IntelliShape handles, click twice on a part (or click until the part turns yellow).

With the cylinder selected, click on the triball icon. (Or press F10, or select Tools -> Triball). The triball should appear on the cylinder centered at its anchor point.

Notice that the triball also has interior handles. Right click on the vertical interior handle. You will get a menu that lets you position the current part relative to another part, surface, point or axis. Select Perpendicular to Face.

After you select this, move the cursor around. As you move the cursor close to a face in they scene, it will turn green indicating that it is the current face. In the scene below, the face closest to the cylinder is currently selected.

If you click on this face, the cylinder will rotate so the selected axis is perpendicular to the selected face. (Note that if you click on the top face, nothing will happen since the cylinder is already perpendicular to the top face.)

Try selecting different faces and different options. Use the undo button between selections so that you maintain your orientation.

Next, we are going to move the cylinder to the block. Without selecting an axis, right click on the center point of the cylinder’s triball. You will get the following menu:

Select the To Point option. As you move the cursor around, points on the block will be highlighted. In the screen dump below, I moved the anchor of the cylinder to the center of one of the faces of the block.

Note: The orientation of the cylinder doesn't change. So if you have rotated the cylinder to an angle, it will move the center point to the point on the block that you select, but it won't align the faces.

Note: You have only moved the cylinder. You have not joined the cylinder and the block together. To see this, click on the scene browser.

Look at the two parts. (Your part numbers will probably be different from mine.) The block and the cylinder are separate.

Aside: If you want to join them into a single part, you can select Shape-> Boolean to perform the Boolean union operation.

Click to undo the move action. Making sure the cylinder still has the triball active, right click again, but this time, select Edit Position:

This dialog box allows you to specify the exact location of the anchor point of the object. I changed all the values to zero. When I pressed OK, the cylinder moved to the origin. Try moving the cylinder around using the edit position dialog box.

With the triball still highlighted, right click away from any of the handles. This gives you general options for controlling the triball and moving the part.

For example, the default is to move the triball and the shape together. Click on the second option (Move shape only). Now when you move the cursor, the triball stays in its original location and the part moves.

Try the third option. (Position triball only). With this option selected, the triball should turn white, indicating that it is the active object. As you move the cursor, the triball will move and the part will stay in place.

Note: You can also select the triball, by pressing the space bar. In the beginning, you are more likely to do this by mistake rather than on purpose. If the triball isn’t doing what you expect, look at its color. If it’s white, press the space bar and it will return to its normal behavior.

Undo the moves and re-select Move Shape and Anchor, which is the behavior that you normally want.

1.4 Copying and moving

Click undo several times until the cylinder is upright again. In the scene browser, select Cylinder. The cylinder in the drawing area will be selected. Click on the Triball tool. Right click on the center of the triball and start to drag the mouse. When you release the mouse, you will get a pop-up menu that lets you move, copy or link the object.

Select Copy Here. You will get the following dialog box:

Changed the Number to 2 and Distance to 2.5. When you click OK, you will have 2 copies, spaced 2.5 inches apart in the direction you were dragging.

Select the first cylinder again. (Check in the scene browser to be sure you have just the cylinder, not the whole part selected.)

Right click on the center of the triball and drag in a different direction. This time select Link Here. You will get the same dialog box. Enter the same values.

You should have two more copies of the cylinder

Hit escape or toggle the triball tool button to remove the triball from the first cylinder. Click on the cylinder until you have the intellishape handles. Now pull on one of the handles to resize this cylinder. The cylinders that are linked copies change when the original cylinder changes. The simple copies do not. Notice that the scene browser indicates which copies are linked copies by using the shortcut icon on the linked copies.

Try changing one of the linked copies. All the linked copies changed. This makes sense when you are working on a part because you cannot always remember which was the original shape. Notice that the scene browser indicates which copies are linked copies by using the shortcut icon on the linked copies.

2. Short review from the previous lab

With the block selected, select View -> Sizebox dimensions Nothing will happen right away. This is a toggle switch for viewing options. Click twice on the block and you will see the dimensions.

Select one of the handles, and right click on the handle. Select Edit Sizebox. You will get a dialog box that allows you to change the length, width and height of the box. How do you know which way the dimension will change? It will change the dimension in the direction of the handle that you selected. Change the length and press OK. IronCAD changes the length of the box by moving the left-hand face.

To change the resizing behavior, right click on a face of the block and select Intellishape Properties.

You will get a dialog box with many tabs. Select the Sizebox tab. Notice that you can change the length, width and height of the part in this menu as well as change the default behavior of the resizing operation. Pull down the menu next to Length and select About anchor.

Look at the Interaction tab. This tab allows you to control how shapes are combined when you use drag and drop editing.

3. Putting the small holes in the fan plate

Open fanhousing.ics from your desktop. This file has everything except the holes in the corners and the beveled edges. Zoom in on one of the corners by selecting the magnifying glass with the window.

3.1 Locating the hole

Select (normal left click) the center of the triball. With the shift key depressed, move the cursor until the center point of the arc for the blend is highlighted.

3.2 Copying the hole

Strategy: We are going to move the triball to the center of the fan housing. We will then make 3 linked copies of the hole, each at 90 degrees from the original. The holes should be linked because if the diameter of one hole changes, they should all change. Zoom out to see the entire part.

Press the space bar once. The triball should turn white. This allows us to move the triball without moving the part. Right click on the center of the triball and select To Center Point.

3.3. Blending

To see how these options work, lets start with a practice part. Drag a block into your drawing area, away from the fan housing. In the first option, select Face/Edge/Vertex. In the second option, select constant, and in the third option, select 0.158. (These are probably the defaults.)

Move your mouse around the block. Your cursor should change shape. The cursor will look like a dot when you are close to a vertex, the point at which several lines and faces meet. The cursor will look like a line when you are close to an edge, the line where two faces meet, and it will look like a sheet of paper when you are over a face, one of the surfaces of the part. (Again, since the cursor doesn't show up in the screen dumps, I can't show you this.)

First, select a vertex. Notice that IronCAD shows you where the blends will be applied.

If you want IronCAD to make the indicated blends, press the green go button. If you don't want IronCAD to make the blend, press the red X button.

After you make this blend, press the undo button, and then try the other options to see how blend works when you select edges and faces. Notice that the blend toolbar disappears after the blend is created. You need to select the blend tool again to get it back.

Finally, change the type of blend from Constant to Variable. You will now be able to enter a start and end radius for the blend. Press the go button again. Here is a variable blend on a vertex:

Now we are ready to blend the corners of the fan housing. Press the blend tool button. From the drawing, we know that the blend radius of the corners is 0.217. Enter this value for the blend radius and check to be sure that the blend radius is constant.

From the pull down menu on the left part of the blend tools, select Edge. This will ensure that only edges (not faces or vertices) will be selected -- although you still have to be sure that you pick the right edge.

With the blend tool on and the blend radius set to 0.217, select one of the edges (lines) at the corner of the part.

sfinger@ri.cmu.edu