Thanks to everyone for the concern and advice. As it happens, I cannot afford to spend any more time on Sketchup at this point... I have already slighted some other activities that are more urgent.

I still hope to return to the tool at some point in the near or more-distant future when I can devote some time to it. Knowing there is such a supportive community will be a major motivator, and I will be trying all your suggestions then.

Thanks again.

I appreciate the generous offers of assistance. It actually wasn't intended as a cry for help, because when I describe what I'm trying to do simply enough to post a description, I can do it myself. But somehow when I do things in context the work crumbles.

[Incidentally, tomsdesk is right: "I give up" and "I needed something like this" don't fit. The second quote should have been "Something like this would have been valuable".]

It's not any particular thing that I'm trying to do... it's that SU never ceases to surprise me by doing something I don't expect and don't want. Things end up where I don't want them, refuse to be moved to places where I do want them, and are sloppily aligned (and I don't know how to line them up). I have tried unsuccessfully for hours to draw a particular polygon face. The symptoms range from incompletion (i.e. it doesn't turn blue) to overcompletion (it turns blue and so does a previously hidden wall). I have tried using guides (tape measure and protractor), axis shifting, image tracing, and freehand sketching followed by moving the vertices. For one glorious moment I had something that looked OK (this would be on perhaps attempt #13 out of 19) but it didn't last.

I've concluded that I just don't think like ST, despite two or three days of effort. There's no way to know whether it would take another three days, or three weeks, or three months to get the hang of it.

I tend to pick up software fairly quickly and exploit it more deeply than many of my colleagues, so I don't think raw candlepower is the problem. In fact I have no clue what the problem is--if I did, I'd try to address it.

There are lots of people doing terrific things with the product. I still look forward to joining the group someday when I'm able to devote a lot more time to it.

</whine>

In spite of all the helpful advice from forum members, and several hours absorbing all the 'for dummies' videos (on top of the Google intro videos), I still can't see how to do what I want to do with Sketchup.

It's too bad. I needed something like this, and it would have been very useful if I'd been able to figure it out.

Thanks to everyone for so many quick responses. For reasons that still baffle me, the first two or three times I checked back I couldn't find my post and so couldn't benefit from your help until now. So I've unfortunately been continuing to attack this on my own. FYI this is where things got to:

(1) Shapes sticking together: Group solved it, as Remus pointed out. And thanks to Jon for the clear distinction between Groups and Components.

(2) Controlling the position of a shape: For whatever reason I didn't have any luck using the arrow keys to move objects (as Charlie suggested); must have been misreading the instructions. Triggered by other posts in the Forum I tried Nudge (from Smustard), and it did the job nicely.

(3) Drawing a line to my own points rather than SU's: Still no luck on this one. Didn't manage to enlist VCB. What I've ended up doing is creating temporary faces, using Nudge to move them so their corner points are where I want my line bends, and then drawing the line. The inference engine helpfully forces my line onto the temporary objects and I delete them when I'm done. It gets the job done, but there must be a better way.

Thanks for all the other useful tips: mirjman on construction lines, Gaieus on axis alignment, Ross on X-ray mode and the Sketchup for Dummies site. I'll be using all of them.

SU keeps making assumptions that it must think are helpful, but that make it impossible for me to get useful work done. For example:

--Shapes somehow get glued to shapes that they aren't touching and have no (logical) connection to. Then when I move one, the other gets dynamically distorted.
--When I try to position a shape, SU lets me put it everywhere except where I want it. I've read the help on Snap, and on Move, and have tried holding down all the key combinations that have occurred to me, but haven't figured out how to turn this off.
--When I'm drawing a line, SU insists on making its endpoint lie on a nearby green dot, even though that screws up my diagram. I can't figure out how to override it.

I've taken the self-paced tutorials, and the older general-intro video. I've read through all the tips. I've searched the help file, and at least scanned all its pages. I confess that I haven't devoted however many days it would take to view all 25 or so videos.

I'm hoping there are one or two key insights that I'm missing that can switch me over to productive baseline-level use of SU. I'll appreciate any suggestions of what they might be. Thanks in advance for any help.