Fusion invisibly multiplies parameter by 10x

[cullenjwebb]

Hello!

On occasion a parameter results in much larger values than expected. Reviewing the parameter list does not reveal anything until I change the parameter unit type to mm, in which case it is shown that the parameter is actually 10x what it is supposed to be.

Example: parameter1 should be 1mm, but when extruding the result is 10mm. The list of parameters shows that parameter1 is correctly set to 1mm, but changing the unit to something else reveals that it is being treated as 10x the intended value.

These are newly created parameters on a model I started just today. Screenshots show that  parameter that was supposed to be 1 (unitless) converts to 10mm when I change the unit type. No matter what I do, changing the expression to something other than 1 and then back, or changing the unit type to mm back to unitless, it always reverts to 10 instead of 1.

This has also happened in the reverse where a mm unit would be 10x the intended value and converting to unitless would reveal the error.

[HughesTooling]

@Phil.E Is this correct behaviour?

Seems to me changing the units on existing parameters doesn't work very well (this feature was only implemented recently). For example if you create a parameter in mm then change to uniless the expression changes to something like (1mm )/mm. If you then want to edit the expression you have to keep that format, you can't just enter 10 like you could if the parameter was actually created as unitless to start with.

Here's an example of a parameter create in mm then changed to unitless then edited to 10. As you can see I can't now use the parameter as a unitless parameter

And something similar happens going from unitless to mm, 1 becomes 10! To get the value to match the expression you have manually add the units.

Changing from unitless to mm gives you this.

You then need to add mm to the expresion.

But you still can't use the parameter in a feature.

You also need to multiply Test by the units! So the parameter is still acting like it's uniless.

Edit, Just noticed this doesn't work because multiplying by the units actually gets you 0.1mm.

So after just changing the units an expression of 1 has a value of 10 which would work in an extrude if you enter Test*1mm but if you edit the expression mm is automatically added to the number so any exiting features will end up 10x too small.

These problems have come up on the forum a few times and usually it's just easier to delete the parameter and create it with the correct units. The ability to change units in the parameter managers just seems a waste of time if it doesn't actually change the parameter's units.

Thanks Mark

[Phil.E]

Thanks @HughesTooling I sent this to the parameters team in the ticket FUS-150304. Definitely seems like it doesn't really do what it says.

[Phil.E · Accepted solution]

The major update that came out last night should have a fix for this. Please give it a try and let us know how it works for you. (build 2.0.18719)