Unexpected behavior in user parameters, 1.5 ft does not equal 18 inches

[731n37]

Hi all,

I have encountered an issue with user parameters where 1.5 ft apparently does not equal 18 in. To calculate the number of studs needed to fill a wall, I am using the length of the wall divided by the stud pitch. A robust formula will be more complicated than that, but it's the starting point. However, there seems to be a difference between the expressions:

floor((BuildingLength) / (1.5 ft))

and

floor((BuildingLength) / (18 in))

with the top expression returning 17 and the bottom expression returning 12 for the same fixed value of the variable BuildingLength. I've also tried replacing BuildingLength with a fixed value and the delta persists.

I'm running v2.0.9719 (Fusion 360, Personal) on Windows 10. Any help would be greatly appreciated, seeing this delta reduces my trust in more complex expressions so for now I'll be manually validating the results of everything until I understand what's going on.

Thanks!

EDIT: I realized that I neglected to post the screenshots of the variable window.

[jodom4]

Hey 731n37,

Thanks for bringing this to our attention! I've passed it along to the appropriate team, hopefully we'll be able to fix it soon.

[nigel76FS8]

There's a related bug I noticed just now, along the exact same lines, but more blatant. One of those imperial measurements is not like the others!

How come the parameters all resolve into metric, in the righthand column, except one, which is in inches still? Even weirder, the model itself still works!? How do I change that one that's decided to be in inches to mm? How does that even work, that some of the units resolve and others don't?