Constrain to midpoint?

I'm using (learning) Inventor 2013. I'm trying to place various simple parts into an assembly but I'm having trouble trying to position/constrain some parts.

Specifically, I'm trying to place one piece of flat bar onto the center of another. I know how to constrain edges & faces, but there has to be an easier way to constrain to a midpoint than calculating the offset from a face. I've tried putting in various axis on the mid-line of the parts, but the axis are not recognized when adding a constraint.

I'm used to modeling in Autocad where this would take me half a second.

You should be modeling with obvious symmetry about the origin. Then it is a trivial matter of mating the workplanes.

If you can't figure it out - attach your assembly here.

and read this http://home.pct.edu/~jmather/SkillsUSA%20University.pdf

You should be modeling with obvious symmetry about the origin. Then it is a trivial matter of mating the workplanes.

If you can't figure it out - attach your assembly here.

and read this http://home.pct.edu/~jmather/SkillsUSA%20University.pdf

Unfortunately, the people that created the structural shape parts in Content Center didn't read your PDF, JD. Origin for those is almost invariably in a bottom corner somewhere, instead of the middle of the part.

Actually, the few structural members I've used are actually created around the origin, which has (in part) solved my issue.

So another, somewhat related, question...how do I (or should I) align parts to a sketch? For example, I make a sketch to define a layout, but I can't constrain anything to the sketch lines.

It sounds like you're using a sketch in an assembly, rather than a sketch in a part? If that's the case, then no, I don't think you can constrain to it.

Really, you should use axes / faces / planes for constraints whenever possible, rather than sketch geometry. If you plan ahead, your constraints will still work after you change something.

Thanks. Yes, I'm starting to see that a sketch, on it's own, in an assembly is useless.

What I ended up doing on my current project, was to place work planes where I needed the members, then constraining the origin planes of the member to the new planes in the assembly. That seems like a better (proper) way to do it, but it didn't seem all that intuitive to be setting up the new work planes and controlling their locations.

I haven't yet had much experience with the Frame Generator, but that seems to do just what I want. Being able to constrain and change member locations in an assembly, by simple editing a sketch.