Grasshopper decimal separator

the decimal separator is somehow messed up in Grasshopper.

Can’t set a decimal number manually.
The only way is by the slider.

Video attached.

I have found that running Grasshopper changes the System.Globalitation.CultureInfo.CurrentCulture of RhinoCommon, the problem is linked to that change.

I’m italian, we use a comma as decimal separator. I dislike that.

Luckyly, if I use the numpad in my keyboard, the dot ‘.’ is correctly used as dot ‘.’ in my computer.
It isn’t the same for you?

4,5 is interpreted as a vector x=4 y=5 z=0 , and using it as a number you get the length of that vector, 6.403… 41^0.5


Great finding! … and a great example why implicit type conversion might not be such a good idea.

When I have to create a simple but specific and static point/vector I usually use a small panel with something like: “1,1,0” or “1,10,1” etc etc… I personally like this option.

But I agree that grasshopper converting the type of a data/object/value without telling it to the user is sort of problematic, particularly for new users (once you use it for some time, you expect it).
Some small UI trick would be enough, like the connection wire changing color at the end, or even the component itself or the small circle for the input parameter…

Hey Riccardo,
I’m italian too.
As you can see from the video, the decimal separator in the slider is a comma, not a point.
Since Grasshopper uses point as a separator, it unsets my current culture.
It does this even in rhinocommon. To fix this problem, a Rhino plugin that I am using (developed with Rhinocommon), was resetting the current culture to the previous active one when no one is set.
And that’s why Grasshopper is using comma as separator and not working as intended.

So the problem is related to the hidden implicit type conversion and Rhino plugin resetting it.

Fixed the problem not resetting it anymore and not using the CurrentCulture in rhinocommon anymore.

Europeans should accept point notation for decimal separation, and Colonials should accept SI units for any form of applied science and engineering. That would really make software development easier. But it’s the ideal world, right…

Rule number 1 in anything you do in life, if your user-role is “peasant” you should only do what you are supposed to do… The sooner you accept the truth, the easier life becomes. I doubt someone will rework this, as stupid and wrong implicit (& hidden) type conversions and missing culture support might appear.


The Italian keyboard numpad have a point/dot, not a comma.
It’s a start. :sweat_smile: