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Magnitude of value with units

konstantin_shiriazdanovkonstantin_shiriazdanov Member Posts: 617 ✭✭✭✭
How to extract unitless magnitude of value with units if the units are unknown? Or what is internal structure of ValueWithUnits type, is it of map type?


  • paul_chastellpaul_chastell Onshape Employees Posts: 82
    edited July 2017
    I would suggest you divide by the unit you are interested in, and ignore the internal representation. If you have a length and what to know how many meters it is then you can do "var lengthInMeters = length / meter". It doesn't matter what unit 'length' has. Or "length / inch" to get the length in inches. In both cases the result is a unitless value.

    E.g. this custom feature measures the distance between two points, in inches, and logs it to the console

    annotation { "Feature Type Name" : "Distance in Inches" }
    export const inchDistance = defineFeature(function(context is Context, id is Id, definition is map)
            annotation { "Name" : "Points", "Filter" : EntityType.VERTEX, "MaxNumberOfPicks" : 2 }
            definition.points is Query;        
            if (size(evaluateQuery(context, definition.points)) == 2)
                var result = evDistance(context, {
                    "side0" : qNthElement(definition.points, 0),
                    "side1" : qNthElement(definition.points, 1)
                println("Distance in inches is: " ~ (result.distance / inch));
    Paul Chastell / VP of R&D / Onshape Inc.
  • ilya_baranilya_baran Onshape Employees, Developers Posts: 782
    Paul is absolutely right.  But if you're curious about what the representation is, you can look at units.fs in std or do println("" ~ inch);
    Ilya Baran \ Director of FeatureScript \ Onshape Inc
  • konstantin_shiriazdanovkonstantin_shiriazdanov Member Posts: 617 ✭✭✭✭
    ok, thank you Ilya and Paul, I found out that ValueWithUnits is internally a map and "value" field contains magnitude
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