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berol

Autocad 2000, no plus or minus shown using toolbar ordinate command

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Have placed my Absolute Datum 00 for both X & Y axis at the lower right hand corner of my rectangular part. Have dimensioned my part using the toolbar ordinate tab. I know from previous experience that some axis positioning is going to be negative when I go to drill these holes with my mill. With the absolute datum at the lower right corner & because of the size of the part it will be in quadrant 2 of the Cartesian plane. Why then don't some dimensions show as negative? Thanks

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AutoCAD uses the absolute coordinate value of the current UCS to determine the ordinate value. So there will never be a negative value.

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Not sure I understand. When I look at a diagram of the Cartesian Plane, quadrant 2, the upper left hand quadrant shows -X and +Y. When I input ordinate dimensions into my digital readout on my mill that move to that quadrant 2, the X needs to be negative & the Y positive.

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When AutoCAD set up the ordinate dimension system, they seemed to have set up a datum point that was to the left and lower than any features. So they expected all dimensions to be positive and thus took the 'absolute' value of any dimension.

 

I don't think that they considered anyone to be devious enough to go to the left and down from the datum point.

 

You and I know about the various quadrants, but AutoCAD apparently does not for ordinate dimensions. You can always override the text.

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