Extruding and subtracting regions

- The next area to focus on is the seat. Go ahead and orbit, and then type l-a-y-i for layer isolate. Make a crossing window around the seat and the top of the seat tube. And let's orbit around a little more, and zoom in. So the first element that we're going to model in regard to the seat and the seat post is this clamp, right here that holds the seat tube in place. Let's create a new layer, called 3D post clamp and, I'll turn that on, make it current, and color it yellow to match the frame.

It's welded to the frame after all. It's part of the frame really, but I have it on this separate layer for convenience. So now, u + c + s + enter, o + b for object, enter, and click on this line. Draw a rectangle, from the quadrant of this circle over here, like that. Then select it, and grab this grip, and move it inside the seat tube, some distance. Then draw a circle, to match this inner one, and another circle to match the outer one.

Type r-e-g enter, for region, and, select the rectangle in the outer circle, and then subtract, the rectangle, enter, and then the circle, enter. You're left with this shape. Extrude that, up five millimeters. Now, we have this portion that sticks into the tube, we need to get rid of. u + c + s + enter, x, enter, enter, to rotate the coordinate system onto the side, and then draw a circle, over here, and extrude that, last object, back some distance.

And then subtract, select the object you want to keep first, enter, and then select this cylinder, enter. Now we need a tube, so let's go u + c + s + p, for previous, then draw a circle, centered here that has the radius of the outer circle. Then, convert, both of those yellow circles into regions, and subtract, select the outer circle, enter, and then select the inner circle, enter.

And then extrude, those up nine, and then union these two pieces together. Let's move this up, one millimeter, and then, change the UCS to be on the side again, u + c + s + enter, x, enter, enter, and then mirror this object. The mirror plane will be, right down here, and I need to move the cursor around to find the right orientation. I will click and press enter, to mirror a copy around to the other side.