Creating a rectangular object on top of a cylindrical one

Sometimes it's ok to struggle. Sometimes it's annoying. When I was modeling a mechanical pencil I struggled for about 45 minutes trying to get the rectangular clip of the pencil onto the pencil body itself (which happened to be a cylinder). Every single ^%#$ time it would say that it needed one more constraint and then I would add it and BAM! "your sketch is over constrained". I hate it when sketches get over constrained. Do you??

Sometimes it’s necessary to create a rectangular shape that’s on top of a cylindrical form. The question arises “how does one fully constrain this type of sketch without making a separate piece?" If you're completely new to CAD this is a guide that I hope will help you figure some things out

1. Create the cylindrical form that you will place your rectangular piece on by sketching a circle and extruding it.

2. Start a new sketch that lies along the curved surface of your cylinder.

3. Create a rectangle that lies approximately on the “edge” of your cylinder but is in fact inside your cylinder so that it can be properly united to the cylinder at a later step. Alternatively, you can start making the rectangle from the center of the cylinder and building it out pas the cylinder wall.

4. Create the proper dimensions of your rectangular object. Since there is no edge on the cylinder to constrain your rectangular object to, you must create dimensions between the rectangle and two of the axes.

5. Exit the sketch and extrude the rectangle. If you want it to be symmetrical on both sides of the cylinder be sure under “limits” to select “symmetric value” under “end”

6. complete the extrusion

7. You should now have a rectangular object on top of a cylindrical one!

Wow. Don't you feel good about yourself? I sure did. (Thanks Jonathan). Now you are on your way to using NX!!!