@tig said:

Or perhaps this ?

TIG,

Almost, just like gilles! In any case, you have both taught me about the value of fixing up the drawing before I push/pull.

TIG, if I were able to take the form at the end of the sequence you showed, and then move the walls of the cylinder UP so that bottom of the cylinder is coplanar with the top of the square, then I would have the shape that I need.

I'll play with the method you demonstrated to see if maybe I can modify to do what I need.

However, this does seem to bring to light an annoyance of SU that I hope there is a workaround for. Your solution makes sense if one starts knowing the exact shape one is trying to draw - but in my case, I didn't decide to add the "basement" (the square portion) until after I had already put considerable drawing effort into the first floor (yes, I'm designing a house). When I drew the square, its lines intersected with the bottom of the cylinder. If I delete those lines as you suggest, then the cylinder starts losing walls.

I've tried many means of trying to "turn off" the interaction between the circle and the lines (hiding them, putting them on different layers, etc) but SU seems to insist that the border of the circle must be a boundary when I try to extrude the square. Any suggestions?

Thanks
-Ron

@gilles said:

1,2,3...

Is that what you need?

Gilles,

Almost! I just need the box to be extruded DOWN from the sketch plane, not up.

I'm trying to create a simple shape consisting of a hollow cylinder with a certain wall thickness (say it's 10 ft in diameter, with a 6 inch wall, and say 10 ft long) and a square extrusion that shares the same axis as the cylinder and the cylinder circle is inscribed in the perimeter of the square. The situation (prior to any extruding action) is shown in the attached picture. The purple portion represents the base sketch of the cylinder. The grey portion represents the base sketch of the rectangle.

I would like to pull the cylinder wall "up and away" from the green base object, and push the square wall "down and into" the green object.

When I go to push/pull either the rectangle wall or the cylinder wall, I get an incomplete extrusion. What I mean by that is that portions of the wall are missing at the place where the two sketches intersect. I've shown an image of the problem in the second attached image.

How do I avoid this behavior? If I start deleting lines, then I have to chose whether the square or the circular portions get to have a complete wall.

Thanks for any help.