Wow, thanks very much goga, that's exactly what I needed!

First off; sorry if this question has been posted already, I have had a look through the forums already but can't quite find what I'm looking for, and being a complete DC noob I'm flumoxed.

So basically, I have box representing the massing of a building. I want the height to remain fixed, and the foorprint / floor area to remain the same.

Let's say for argument's sake the box is 4m tall and it has a floor area of 150m[sup:1dnvl6tj]2[/sup:1dnvl6tj] - how would I make it so that if I were to reduce LenX using the scale tool, LenY would increase to keep the square meterage the same?

e.g. LenX*LenY=150m[sup:1dnvl6tj]2[/sup:1dnvl6tj]

Thanks for taking time to read this

Well, I ripped out all the Fredo related plugins and all their relevant bits, then re-inserted freshly downloaded versions; lo and behold, it works! I'm confused as to why, because as far as I can tell, the plugins' file path structure is exactly the same as before.

In any case, thank you everyone for your help!

Yeah, I think something is messed up with my plugins directory or something, because I'm not getting a lot of the snaps and inferences I should be... I'm going to go check that out.

As far as I can tell, I've duplicated everything exactly as you guys have done it, but I must be doing something wrong. I'm getting a snap for "Endpoint" "On Edge" "Parallel To Edge" - nothing works.

Thanks for trying guys

Edit: Yeah Massimo, I tried just edges too; no luck I'm afraid.

@massimo said:

Try to hover along the target rectangle's edge while rotating and you'll find it.

Yeah, that just isn't happening.
I honestly don't know why...

Gilles, allow me to clarify: it took me a minute to think I'd worked it out. Turns out the problem it a lot more complicated than I had initially thought! I'm still trying to work out how to do it.

Massimo, I cannot, for the life of me, get the ornage line to come up! Now, I know this can't be a plugin age issue because I only installed SketchUp on my work computer a few days ago and went searching for all the plugins I need, which are all up to date.

Is there a trick to getting the orange edge?

I've obviously just misinterpreted you then; no apology needed.

I'm still stuck on this one though

I have been nothing but courteous to you, Dave, so I don't understand your tone. At no point did I say anything to warrant your rudeness. I am legitimately requesting help using the best descriptive language and images I can and I have been met with a condescending attitude.

I have tried to do exactly what you outlined, but I cannot achieve the result you have. It's hard to tell from the screenshot you've posted, but when I get something that looks like that, zooming in reveals that the faces are either slightly overlapping or not quite touching, no matter how hard I try. I initially thought your solution was viable but realised that, at close examination, it wasn't quite there.

I genuinely appreciate you taking time to try and help me out, but either I'm misunderstanding your instructions or I'm using the tool wrong, and I don't think either is the case after trying it every-which-way.

I apologise if I've come across as ungrateful or contrary, that wasn't my intention.

The thing is, Dave, I tried it the way you suggested and even after 10 minutes of playing around with it I couldn't get it to work the way I need it to, which is to make the top edge of the piece I'm rotating line up exactly with the face, not point to its vertices.

I didn't download these plugins willy-nilly; I'm aware of their functionality to the degree that I regularly use them for practical applications, so please don't assume I have just thrown up a request for help without first trying to find a solution elsewhere.

Gilles, nice challenge. Took me a minute to work it out

Both these examples, however, rely on the variable being the length of the diagonal element in order to meet the vertical face. What I need is a way of keeping everything but the angle of rotation exactly the same and making the edge touch the face as described above.