Moving along the design process for the air hockey paddle, I realize I want the box rib to be flush with the top of the cylindrical plate. I’ll change my viewpoint so that I’m looking at the plate from above and then I’ll select the base grip (the square grip in the middle) and move the box to the center of the top of the cylinder (using the CEN osnap of course). Since the cylinder is thin, the top and bottom center points are close together. You have to be careful to select the right one. You can apply the same trick that you use in 2D (and probably don't even notice).
For example, if you have a 2D drawing with two circles that are very close to each other and you want to pick the center of the circle on the right, you would position your cursor to the right rather than in the tiny gap between the two circles. This ensures that you get the “right” circle. The same logic applies in 3D!
Now the base of the box is in the right position but the height is going the wrong direction.
I want the top of the box to be flush with the inside of the air hockey paddle. If I knew the value for that height, I could enter it in the Properties palette but it would still be going the wrong direction. I’d first have to grip-edit the height so that it’s above the base and then enter the appropriate height value. I don’t know the value and I don’t want to think that hard. Since I know the top of the box needs to be flush with the inside of the paddle, I’ll grip-edit the box to make that happen. First, I’ll change the viewpoint to look at the model from below. Then I’ll select the box, pick the height grip, and select the bottom inside edge on the air hockey paddle. Since the height grip is constrained to moving in one direction (along the Z-axis in this case), it doesn’t matter that we’re snapping to an object with random XY values.
Viewing the model from above, you can see that the box is now protruding above the cylindrical plate and you can rest assured that when the plate is inserted in the paddle, the top of the rib will be flush with lower inside face of the paddle.
Next, we need to modify the width and length of the box. I’ll use the Properties palette to set the width to 2 units.
I want the length to be equal to the diameter of the cylinder. I could enter that value in the Properties palette, if I knew it. But, I don’t know it and I don’t want to think that hard. Instead, I’ll select each of the length grips and then snap to the appropriate quadrant on the cylinder. The length grip is automatically constrained to move along the length axis so it doesn’t matter if I pick the upper or lower quadrant grip.
• Using the Properties palette to modify the size and shape of a 3D solid box.
• Using grips to modify the size and shape of a 3D solid box.