by Justin Doughty
In AutoCAD most users are familiar with the Scale command. However scaling AutoCAD elements in practice can prove difficult if trying to just use scale factor to resize the elements.
This is where Scale by Reference is useful, we can use this to scale “from” a certain size “to” another.
In the example below the basin circled has been inserted into this drawing at an unknown scale:
The basin should be 500 units wide, so to correct this, we run the SCALE command as normal, picking the corner of the basin as a basepoint.
When we get to this point, we select Reference:
It will then ask for reference length, use snaps to pick the endpoints of the basin’s width.
It will then ask to specify a new length, we know the correct size for this, so we enter 500.
The basin has now been scaled to the correct size, by using these 2 reference lengths:
Scale by reference can be used for a variety of uses if you have a known dimension. Some examples are scaling elements to their correct size, scaling standard elements to fit a set length (say between two walls) or even scaling an entire drawing!