topic Re: Can't provide expressions when expression evaluates to zero in Fusion Support Forum

Can't provide expressions when expression evaluates to zero

mamassey — Fri, 15 Feb 2019 03:32:50 GMT

When an expression evaluates to zero, Fusion 360 will not allow it to be used as a sketch dimension or inputted into a dialog box.

This can be a problem when a model is to be used used frequently and some parameters will cause an expression to be zero under certain circumstances.

The issue can be resolved by temporarily supplying parameters that cause the expression to be non zero then changing those parameters back again. The expression will return zero when this happens.

Expressions that evaluate to zero should be allowed.

Re: Can't provide expressions when expression evaluates to zero

jeff_strater — Fri, 15 Feb 2019 03:43:54 GMT

zero is not a valid value for a sketch dimension, and for some other inputs, as well. The bug is the fact that it is possible to drive a sketch dimension to zero with an expression - that should be disallowed, as well.

Re: Can't provide expressions when expression evaluates to zero

mamassey — Fri, 15 Feb 2019 03:57:11 GMT

Fair enough sketch dimensions shouldn't be allowed to be zero, there's alot
of difficult edge cases there.

I'm currently working on a model that has alot of computed trig
expressions. Often they will evaluate to zero, but not all the time.

In this particular model there are also cases where faces need to be offset
relative to an angle, sometimes the offset should be zero.

I think that if a negative value is allowed for an input, then a zero
expression should also be allowed.

Re: Can't provide expressions when expression evaluates to zero

jeff_strater — Fri, 15 Feb 2019 04:14:54 GMT

thanks for the response. I understand that this limitation can be a problem in certain situations. Unfortunately, that's the way it works today. I'll pass on the suggestion to the development team.

Re: Can't provide expressions when expression evaluates to zero

mamassey — Fri, 15 Feb 2019 04:36:32 GMT

Also, while I've got you...

In this case, the ability to reference driven dimensions would have removed the need for zero returning expressions.

Just sayin'...

Re: Can't provide expressions when expression evaluates to zero

busycleta — Sat, 06 Mar 2021 19:42:49 GMT

Hello @jeff_strater

In order to have a consistent user interaction with the sketcher, or any other feature of a CAD for that matter, zero is as valid as any other rational number to be an input as a driver for a geometric operation. Imagine you cannot dynamically control your model to contain touching or clearance between parts.

Unfortunately until today (years later) the bug remains in that a valid input (zero) is only then evaluated, if the user relies on a very questionable, non controllable cumbersome hack (as described above)

Why not just get rid of the hindering type check to allow zero just like in any other professional CAD software?

I get the point, that F360 targets the makers who can spend hours and hours with mousclicks, for engineers and product developers however, a behavior as expected would result in a much smoother experience.

People fond of excessive amounts of mousclicks can then still do that, they won't be bothered by the behavior as expected.

See Details here:
https://forums.autodesk.com/t5/fusion-360-support/zero-is-a-number/m-p/10131264/highlight/true#M115550

thanks