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    Autodesk Inventor

    Reply
    *Genova, Jon

    model dimension tolerances

    19 Views, 0 Replies
    11-21-2002 03:52 AM
    It appears that you cannot have mixed precision tolerances display
    properly in a part model. I'm trying to capture design intent in a
    part where only a few features requre .1234 place precision. Normally
    .123 place precision works for pretty much everything we do. For this
    example, I'm making a cube with one precision hole reamed thru the
    middle of it.

    With Tools>document>Linear dim precision set to .123 places

    Create a block 1.000 x 1.000 x 1.000
    Bore a hole thru it with a circle extrusion of diameter .250

    Switch to feature priority selection

    Double click on the bored hole- the dimension of the hole pops up.
    Select the .250 dimension, RMB, select Dimension Properties...
    Change the Precision to 0.1234 (expecting the tolerance also to follow
    this format)
    Select Deviation from the Tolerance Type- Upper= .0005, Lower .0000

    Hit OK

    The dimension shows .2500 +.001/-.000

    Shouldn't it display like: .2500 +.0005/-.0000 ?? Um... I think so!


    Now try this:

    Goto Tools>document>Linear dim precision set to .1234 places
    Hit the Update button or select Tools>Rebuld All

    Now you see four place precision (.1234) on both the dimension and the
    tolerance.
    Problem is, all your part dimensions are also shown as 4 place.

    If you create a drawing of this block and ask to "Get model
    dimensions", the tolerance for this hole feature is respected as .1234
    precision in the drawing despite what the precision is set to in the
    dimension styles. This behavior is expected, and seems to work
    properly.


    I think the model tolerance should respect the precision set in the
    "Dimension Properties.." dialog to convey proper design intent.




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    Jon Genova
    Senior Mechanical Design Engineer
    BioServe Space Technologies

    A NASA Commercial Space Center (CSC)

    genovaj@stripe.colorado.edu
    Bioserve URL http://www.colorado.edu/engineering/BioServe/
    Personal URL http://stripe.Colorado.EDU/~genovaj/
    Please use plain text.