MEASUREGEOM does not match results from DIM

[Anonymous]

I am working in AutoCAD 2D model space on a dwg file provided by an architectural draftsman.  Dimensions produced by the DIM command seem correct compared to the pdf file I was provided with.  However, when I try using the Measuregeom tool, results are inaccurate by slightly more than 100% larger measurements.   I use the Measuregeom tool regularly, I have no idea how to correct this so I can use the tool when drawing.  I appreciate your thoughts.  Thanks!

[Alfred.NESWADBA]

Hi,

>> Dimensions produced by the DIM command seem correct

>> compared to the pdf file

A PDF file can show some text, but does not show any real dimension as it is scaled to a paperformat and never a 1:1 size.

>> when I try using the Measuregeom tool, results are inaccurate

>> by slightly more than 100% larger measurements

If _DIST shows a different value to the expected value than most probably the geometry you have measured is incorrect drawn.

>> I have no idea how to correct this

You might scale the geometry using option _REFERENCE within the command _SCALE.

But first I would look to the source of the issue. Where are the data from, and at which step started the incorrect size.

- alfred -

[pendean]

Dimensions results rely on dimstyle settings: do these actually match the DWG file's units and scale? You are assuming an apple and a banana are identical because the are both fruit in your post, which they are not.

Please elaborate and if needed provide an actual DWG file so we can all see your work for ourselves first hand: or reach out to your draftsman and you two discuss the issues together first hand if needed.

HTH

[ChicagoLooper]

If you are really working on a 2D model, then use DIMLINEAR or DIMALIGNED because you are restricted to 2 dimensional distances, e.g. from the beginning of the driveway to the end of the driveway where you enter the garage. If you use MEASUREGEOM you are measuring in 3 dimensions, e.g. from the beginning of the driveway to top of the garage door of the garage door entrance.

Since you mentioned you use the MEASUREGEOM regularly, it sounds like you frequently measure 'ground' distances where the surface elevation fluctuates from point A to point B. If you are measuring architectural distances, then you should measure in 2D, not 3D, so the trades don't freak out when they cut lumber, steel and pipe. Inaccurate cuts may make the finished building lean-to-one-side and they might the blame drafter who used the wrong Cad tool.

[Kent1Cooper]

It sounds to me as though either there is actually a Z-coordinate difference [which Dimensions will ignore but which the DIST command {= the MEASUREGEOM Distance option} will "see"], or the Dimension has a linear scale factor applied, either in its Style definition or as an override.  The former is easy to test for -- look at the entirety of what DIST returns, because it includes a delta-Z value and an angle from the XY plane, both of which will be 0 if things are truly 2D.

[Alfred.NESWADBA]

Hi,

>> It sounds to me as though either there

>> is actually a Z-coordinate difference

I think the dimension values would not differ then by 100%, I guess it was a PDF with scale 1:500 or so and the scaled PDF was imported without scaling it back.

But it's difficult to know as long as we don't get any feedback from TO.

- alfred -