topic Trying to round-off dimensions in AutoCAD Forum

Trying to round-off dimensions

Anonymous — Wed, 09 Dec 2020 17:07:56 GMT

I’m having trouble rounding-off dimensions. Attached is a sample. I’m working with drawings that were originally created in the mid-90s by drafters who didn’t have (or know how to use) viewports. All of the drawings were scaled down to fit a titleblock in model space, then the dimensions were overwritten to show the “correct” lengths. Now I’m converting them to modern standards and have scaled everything back up and using viewports as needed.

The problem is the dimensioning. With some, the new dimension in paper space shows the correct dimension but with others it shows odd lengths, such as 7.99” instead of 8”. A good example is “Section 4-C” on sheet 2. If I go into to the dimension settings and try to round off at two decimal places, it keeps reverting to four. I tried changing DIMRND but have the same problem with it resetting.

Also, there are some very odd blocks that I can’t edit. I get the message “Cannot REFEDIT anonymous block” – all I want to do is change the color from yellow to black to make it easier to see them on a white background.

What have I missed or what am I doing wrong? Thanks.

Re: Trying to round-off dimensions

Kent1Cooper — Wed, 09 Dec 2020 17:55:03 GMT

For the decimal-places issue, I think you don't want the Roundoff setting, but the Precision setting [the DIMDEC System Variable]. Here in the Properties for a Dimension object:

And in the Dimension Style definition:

On the oddball Dimensions, some at least are just badly drawn. The left end of the 50.99 dimension at the top of the bigger shape is simply dimensioned to the wrong place -- Zoomed way in here:

The definition-point grip at the bottom should be at the midpoint of the white line, so that the red extension line at the top will coincide with the green line, and the displayed measurement will become 51.00 as in the one at the underside of that same shape.

Re: Trying to round-off dimensions

Kent1Cooper — Wed, 09 Dec 2020 18:09:48 GMT

@Anonymous wrote:

.... there are some very odd blocks that I can’t edit. I get the message “Cannot REFEDIT anonymous block” – all I want to do is change the color from yellow to black to make it easier to see them on a white background.

....

That *X beginning to the Block names for the yellow arrows is from the days [long ago] when a Hatch Pattern was a variety of "Block" with an anonymous name like that. That's why, if you Osnap to their insertion points, they're all in the same place [the SNAPBASE origin in the original drawing from which the patterns were generated at the time they were made], and why the closely-spaced lines that make them up all run in the same direction, regardless of the direction the arrow points, and why every one has its own distinct name [different numbers after the *X]. I think you may be out of luck, and may need to just bite the bullet and Explode them all. The pieces have yellow as a color override, but they're on the same blue Layer as the turn-the-corner Lines that connect to them, so you could set their color to ByLayer and they should be very visible, if not black.

Re: Trying to round-off dimensions

Kent1Cooper — Wed, 09 Dec 2020 18:35:10 GMT

@Kent1Cooper wrote:

For the decimal-places issue, I think you don't want the Roundoff setting, but the Precision setting [the DIMDEC System Variable]. ....

Actually, you can do it with the Roundoff setting, but set the Roundoff to 0.01, i.e. round off to the nearest multiple of that [a value of zero means don't round off at all, but use the Units precision setting]. The four decimal places displayed in the Roundoff slot in Properties are a function of that same Units linear-measure precision setting, not of the Dimension settings.

The DIMZIN setting controls whether trailing zeros are displayed, if you'd rather round to the nearest 0.01 multiple and suppress trailing zeroes [rather than using the DIMDEC setting to limit it to two decimal places]. If you do it that way, a value that rounds to [for example] 3.20 will display shortened as 3.2.

Re: Trying to round-off dimensions

Anonymous — Wed, 09 Dec 2020 23:10:23 GMT

Please accept my sincere thanks for your help with some ugly drawings. I greatly appreciate it.

Re: Trying to round-off dimensions

Anonymous — Tue, 22 Dec 2020 22:17:17 GMT

After doing some experimentation with DIMZIN and DIMDEC I'm still not getting the results that my boss (and our customer) wants. Basically, here it is:

3.375 would round down to 3.38

3.50 would display as 3.5

3.00 would display as 3.0

Is there a combination of commands which would enable that? Thanks.

Re: Trying to round-off dimensions

Kent1Cooper — Wed, 23 Dec 2020 15:29:14 GMT

@Anonymous wrote:

....

3.375 would round down to 3.38

3.50 would display as 3.5

3.00 would display as 3.0

Is there a combination of commands which would enable that? Thanks.

I don't think there is. The first two can be achieved by a precision of 2 decimal places and with trailing zeros suppressed, but suppressing trailing zeros means all of them, so the third item wouldn't be possible. That would require a precision of 1 decimal place, without suppressing trailing zeros, which will make the first item impossible.

It might be possible to write a routine that would look at the measured distances of selected Dimensions, check their decimal content, and with certain results impose DIMDEC and DIMZIN values with DIMOVERRIDE. But that would mean the Dimensions with those overrides wouldn't change appropriately if the dimensioned things were Stretched in certain ways -- you would need to run the routine on affected Dimensions again.