World's most basic question

I'm new to building, so please forgive the noob-ness of this question.

I'm trying to make walls and floors line up, with clean corners, and it seems like more of a pain than it should be. Is there a way to make, say, the top edges of two objects align?

Thanks!

You can use copy selection. Click "create" on an object, tick "copy selection," use the wand on the edge you want the new prim on.

You can drag copies when that makes more sense.

Using the numbers gets things aligned well.

It's best to not make things thin, and to design your building so that it works well with the way the building tools work. It's easier to begin with an easy rotation (like 0, heh) then rotate a copy of the entire thing if you need it at an angle.

The other way is to line everything up by the numbers. Say you have a 10x10 prim at 100, 100, 25. Your wall is .5m thick. Your wall would line up at 104.75 (105, the edge of the prim minus half the thickness of the wall).

Or you can use the gridlines and snap to the grid.

And here I thought the world's most basic question was "How do I get this box off my head?".

Anyway, Seldom, there are about a million ways to line things up. My favorite for most situations is the on-screen rulers. In the editor, turn on Use Grid. Then when you go to move things around, you'll see white ledger lines appear on the screen. Move the cursor onto the lines while you're moving the object, and you'll see that the object will snap to the lines. It works really well.

SL is lacking a lot of things that dedicated 3D modeling programs have, but the rulers are one thing it's got that I wish other programs would adopt. They're incredibly handy.

Learn to use all three ruler modes: World, Local, and Reference. World, as you might expect, orients the rulers to the six cardinal directions: north, south, east, west, up, and down. Local orients the ruler's rotation and unit size to the rotation and size of the currently selected object. Reference orients the rotation and size to a referenced object (select an object and press shift-G to reference it).

You'll find yourself switching between the three modes constantly as you work. With consistent intelligent use of rulers, your alignments will always be perfect.

You are showing your age Chosen they changed the default attchment point more than a year ago, but I loved the joke. And the advise, we can all learn somthing new by reading what others think is a simple question, I did this time, thanks.

Thank you all for your great and patient responses. They helped a lot!

I thought it was "You want to make the sexi-sexi?"

P2

did he not mean corners at a 90 degree angle? like an L shape...?

He did specifically mention the top edge.