Contributed by vung.
Press N (you must have the mouse pointer in the 3d window for this to work).
A menu containing these properties will pop-up, the properties you have available to work with will depend on if you are in edit mode or not(more options out of edit mode).
If you have more objects selected only the properties of the active one will change.
Contributed by B@rt.
Hold down CTRL to snap while performing the following actions:
Translations:
CTRL - constrain movement to grid units
CTRL+SHIFT - constrain movement to 1/10th of a grid unit
Rotations:
CTRL - constrain rotation to multiples of 5 degrees
CTRL+SHIFT - constrain rotation to multiples of 1 degree
Scaling:
CTRL - constrain scaling to multiples of 10%
CTRL+SHIFT - constrain scaling to multiples of 5%
Contributed by Michael.
No, Blender is not designed for precision scaling in real world units of measure. If that is what you need there are many good drafting programs available, if you want to use precision scaled objects in Blender you can import them as *.dxf files. Not all programs export fully usable dxf files however.
You can use numeric entry for object properties though: press N to bring up a menu with options.
EDITORS NOTE:
There is a good thread on the blender siscusion server on importing .DXF autocad files.
https://www.blender.nl/discussion/read.php?f=2&i=27054&t=27054
https://www.blender.nl/discussion/read.php?f=2&i=27028&t=27028
Simply create a visual scale in your autocad program then import it to blender. A few things remember about imperting .DXF files is
1 ) Blender imports the drawing as seperate components complex forms usually need to be edited to join vertices.
2 ) Remember to use F-9>REM DOUBLES. Important when extruding 2-D plan views etc.
Don't forget to eat.
Daniel Jircik