I find that the stacking or layering order makes a difference too. By moving what you want to snap to, below what you are moving, sometimes makes a difference, along with zooming in. I also have tried to relax about many aspects of assembly, and eyeball things where I can.
Admittedly, it's a bit unclear as to what is happening, but maybe this will shed some light.
Illustrator does have a setting called "snap to point" -- but it doesn't tell you WHAT snaps to the point, does it? Prior to CS4, Illustrator always snapped your CURSOR to the point -- not the point you dragged. So if you grab an anchor near its edge, you snap the edge of the anchor to another point. I know, this is totally silly, right? It only SEEMS like zooming in help because when you're zoomed in real close, it's much easier to grab an anchor from its center.
In CS4, Smart Guides can now snap OBJECTS to other points. Meaning you can grab a rectangle from its right side and have the left side snap to a guide or another point. This matches the behavior of InDesign by the way.
Thanks for that explanation.
I did notice the difference with snapping and CS4 today.
At first I thought it wasn't working at all, being used to CS3, but then it did what you said, especially after I turned up the snap distance to 8 (max).
This problem was really bothering me so I started messing around.
Grab a path (not a point), hold down the command key, and simply drag/snap to another path.
Yes!!!! A buried pixel snapping option in a vector program is exactly what I've always needed. Not only do vertical and horizontal lines consistently fly around at a rate of 0.5px -- but you are also unable to force it to the correct position by manually typing in the transform box. This handy feature is also a good way to get a new keyboard after smashing the old one with frustration.
Yes it's great for some, and I know others that have been so frustrated by spacing not being consistent as a result of pixel grid snapping. Important to know of it's existence!
Just my 2 cents, but I always work with Smart Guides on (cmd-U), and if I'm having trouble snapping two objects (points, paths, etc) together, I hold down the cmd key and it seems to force it to find a point to snap to. (And yes, I'm on a Mac.)