topic Re: parameters - can't take cube root of parameter with inch units in Fusion Support Forum

parameters - can't take cube root of parameter with inch units

turningGCH43 — Sun, 16 Feb 2025 17:27:33 GMT

I'm stumped by this one, probably a simple solution.

I have parameters:

name units expression value diameter in 27 27 dia_no_units 27 27 D_cube_root in diameter ^ (1/3) <<<< not allowed (stays red) D_cube_root diameter ^ (1/3) <<<< not allowed D_cube_root in dia_no_units ^ (1/3) 3 <<<< works

I can't get cube root to work on values that have units. Also tried power function.

Is there a way to de-unitize a parameter so that I can just use the math function?

Re: parameters - can't take cube root of parameter with inch units

jeff_strater — Sun, 16 Feb 2025 18:01:50 GMT

units cancellation (divide by 1mm to cancel out the units) seems to work

Re: parameters - can't take cube root of parameter with inch units

turningGCH43 — Sat, 22 Feb 2025 16:41:59 GMT

Thanks.
I knew there had to be a way to cancel units. Dividing by units is very unintuitive. I was aware of the multiply by units.

Both seem a little hack-y to me.

Additionally, I did not find this documented anywhere. No mention of it with all the parameter & function documentation that I could find. Maybe I missed it.

Re: parameters - can't take cube root of parameter with inch units

g-andresen — Sat, 22 Feb 2025 17:20:30 GMT

Hi,

@turningGCH43 schrieb:

Dividing by units is very unintuitive. I was aware of the multiply by units.

During my time at school, I learned to set up unit equations in parallel with numerical equations.*
This was a method to reduce errors in the calculations.
It still helps me today when developing equations in Fusion.

günther

* The slide rule and later the pocket calculator knew no units.

Re: parameters - can't take cube root of parameter with inch units

turningGCH43 — Sat, 22 Feb 2025 20:22:51 GMT

Yeah, I totally get and agree that having the units carried along is a good idea and useful as a cross check in a lot of situations. The problem is that it won't let you take the cube root of a linear unit parameter. I needed this for a screw tolerance calc from spec formulas.

now that I know the /unit trick, it's not a big deal.