[QGIS-Developer] Processing data defined parameters in modeler

[Nyall Dawson]

On 10 February 2018 at 01:24, matteo <matteo.ghetta at gmail.com> wrote:
> Hi devs,
>
> I'm playing with the Processing modeler and I noticed something weird
> when using data defined options.
>
> The simple algorithm "Buffer" now accepts the data defined parameter for
> the distance. So I have a simple model with vector, vector field and
> buffer algorithm.
>
> In order to define the distance of the buffer from the field I have to
> use the expression dialog and put the @vector-field-name parameter
> (Field and Value menu shows only one NULL entry)
>
> But it seems  it is not taken for the calculation of the distance.

Unfortunately data defined parameters for algorithms are not yet
usable in models (well, they are, it's just that there's no gui to set
them yet) and can currently only be used through the toolbox.

For this reason the old "variable distance buffer" algorithm is still
available for use in models.

Hopefully in 3.2 we get a GUI for using data defined parameters within models.

Nyall