How can I load data to the Curve Fitting toolbox?

I have x and y data in my workspace, but when I try to select data in the Curve Fitting Toolbox, is like if I don't have nothing in the workspace.

[Valeria Gabrielli]

check the correct use of parentes. If you import the data using ( ), they will be imported as table and won't be in the Curve Fitting Toolbox, if you use { } they will be imported as double and available in the Curve Fitting Toolbox.

[Walter Roberson]

I am not clear as to what it means to import data using {} ?

Answer 1

[Walter Roberson]

The variables will only be found if they are in the base workspace. If you are inside a function, I suggest using

cftool( x, y )

Answer 2

[Chrysi Karagiannaki]

If you have any NaN or Inf values it doesn't allow you to import the x,y,z data. Also, the must be the correct size (in this case prepareSurfaceData function helps). In my case running manully the command Walter suggested: cftool( x, y, z ) helped