Rounding Decimals...

[droak]

I learned in math classes over the many years how to round off decimals. The rules are:

To round off decimals:

1) Find the place value you want (the "rounding digit") and look at the digit just to the right
of it.

2) If that digit is less than 5, do not change the rounding digit but drop all digits to the
right of it.

3) If that digit is greater than or equal to five, add one to the rounding digit and drop all
digits to the right of it.

Examples:

2.1875 > 2.188

4.625 > 4.62

2.25 . 2.5

Auto-Cad seems to have a mind of it's own.

It appears from reading the manuals that the settings should be set in the system variable DIMRND and that if you to not round at all that you should set this at 0.0000 however, that doesn't seem to work completely.

Sometimes the 2.1875 will round to 2.188 and sometimes it will round to 2.187.

Sometimes if my text is inside a circle it will round to 2.188 and if outside the circle it will round to 2.187.

Sometimes if I plot a drawing from one machine it will round to 2.188 and from another machine 2.187.

I draw to factors of 1/64's, this is a through-back to my days of mechanical drafting when I learned what the decimal equivalents were for 1/64 through 1 so I automatically type in the decimal equivalents. But, I use a precision of anything from 0.0 to o.0000 on my drawings.

Can someone tell me how to round off in Auto-Cad by the standard rules that have been used in math classes since the crack of dawn.

Respectfully,
Darrell

[mjfarrell]

The two culprits involved in your confusion are:
http://usa.autodesk.com/adsk/servlet...linkID=2475323

DIMDEC System Variable

Type: Integer
Saved in: Drawing
Initial value: 4

Sets the number of decimal places displayed for the primary units of a dimension. The precision is based on the units or angle format you have selected.

DIMRND System Variable

Type: Real
Saved in: Drawing
Initial value: 0.0000

Rounds all dimensioning distances to the specified value. For instance, if DIMRND is set to 0.25, all distances round to the nearest 0.25 unit. If you set DIMRND to 1.0, all distances round to the nearest integer. Note that the number of digits edited after the decimal point depends on the precision set by DIMDEC. DIMRND does not apply to angular dimensions.