prims not lining

I haveing a major prob building ill try to use a example here. les say i have 2 box prims 10x10x5 side by side the first is x.123.780 y134.733 z 21.598 2nd prim is x133.780 y 134.733 z 21.598 ok acording to the numbers the 2 box prims should be side by side with no open seam or flashing seam from over laping but yet i have found lot of times 1 prim is higher thin the other or seams showing by being open to far apart or the 2 prims over lapping leaveing a flashing seam. i sthis a new sl bug? i been in game allmost 3 years not a expert builder but know somthing ant right lol

I had the same issue. You can check this thread for some tips:

/8/95/121272/1.html

Try and work without using decimal numbers like x124.000 y135.000 z22.000 if possible.
You can also select prims and hit the Shift-X key and it will snap to the nearest x and y grid.
After you are done and hopefully linked the whole or parts of the object. Then position it into your desired location.

When building by the numbers, it is far easier and more accurate to do as the previosu poster recommended, and try to build on the default orientation axis and on whole numbers or readily-evaluated fractions, like x.125, x.250, x.375, x.500, etc.

When you have the build finished and linked, then slide it into the final position, and rotate it if need be.

Me, I like using Ctrl Shift click to copy an identical part onto a selected face of a build.

Somewhere there is a long thread about the way the position numbers are stored, too scientific for me! But in general, even if you build by the numbers or use scripts to position something, the prims' positions are most always going to be a little off, maybe +/- .00001.

For example, this little script from perviously mentioned thread is used to set position of the prim. The build tool position boxes set x=133.900, y=54.900, z=405.350. The Object description has <133.90000, 54.90000, 405.35000>, and after running the script, the said position is: Object: <133.89999, 54.90000, 405.35001>!

// Put this script in a prim and use the format
// <166.764, 204.196, 25.887> +/- .00001
// in the object description

default
{
touch_start(integer total_number)
{
llSetPos((vector)llGetObjectDesc());
vector position = llGetPos();
llSay(0, (string)position);
}
}

Rotated prims do this a lot- ones where the "top" has been changed to face a side, for example.

And it's not a question of coordinate accuracy- to fix them you have to move them to clearly "wrong" coordinates.