Why does fusion 360 make users do mental units and not make assumptions?

[smith9]

I find it frustrating and strange and find so many people spend a lot of time trying to workout why obvious calculations do not work.

It would be a lot less painful if obvious inferences were made in calculations

For example, working out the hypotenuse of a triangle

sqrt(1 + frameWidth^2)

is compact, concise and obvious

but the following could simple be inferred like above without having to divide each dimension by mm in brackets

( sqrt(1 + ( frameWidth / mm ) ^ 2) ) * 1 mm

which is overly complex and a waste of time

[TheCADWhisperer · Accepted solution]

Set up your User Parameters equations in advance as unitless and then apply units when used.

[g-andresen]

Hi,

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@smith9 wrote:

For example, working out the hypotenuse of a triangle

sqrt(1 + frameWidth^2)

is compact, concise and obvious .. and ?

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What should this result in?

sqrt (numerical value + numerical value^2 and unit^2

sqrt       (  unitless                +              unit^2)   ?

günther

[smith9]

Whatever inferences that the developers and business analysts at auto desk deem appropriate. 

If something is squared then square root, then you are back to the same units you started with. It’s a bit like auto boxing in developer languages and not hard to add to parsers. The parsing engine for cad calculation language as most calculators is run of the mill parser language. 

[smith9]

I’ll give that constructive suggestion a try, makes a lot of sense, thanks

[TheCADWhisperer]

You will not like the rest of my story...

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@smith9 wrote:

I find it frustrating and strange and find so many people....

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I have been teaching students for nearly 30 years that they must properly handle unit cancelations. 

They have always been resistant to doing so.

All of the CAD software programs that I use (Inventor, SolidWorks, Creo) handle units the same way I was taught in HS more than 45 years ago.

It is easier if you set up your equations in advance, but this is not really necessary if you have a strong foundation in handling units you can create the equations on the fly as you go.

In the attached file I attempted to reproduce your inference - but I am making a guess about your true Design Intent.

[TheCADWhisperer]

For others who come along and see this - my example above was an attempt to literally reduce to equation what the OP wrote, I don't think it was what he really really intended, but the process of writing a unitless equation and then assigning units later is intent of my example.  (Recognize that 1^2 is a special case, my equation is probably not what the OP intended.)