How to force a node group input field to display a slider?

Question

I have created a couple of node groups with some "group-inputs-sliders" (The one called "Roughness" in the bottom picture). I would like it to have the blue-bar slider like the blender native ones. Thanks (:

Answer 1

Blender 3.6+

Since Version 3.6 and this patch it is now possible to dynamically change the subtype of a field. Expand the right hand side panel with N and go into the Inputs tab. Select the input or output and change the subtype using the dropdown menu.

Image Source

Previous versions

You cannot change a field to display a slider once it has been initialized as a non slider. But it works both ways, if you initialize a field with a slider (Such as a factor input in a mix RGB), and then change the input to something else, the input will keep its slider.

Explanation :

CTRL + G to group several nodes.

You can get rid of the Mix RGB afterwards.

To remap the min and max values of the slider, when inside the node group, open the "N" panel with N or click on the left facing arrow in the top right of the screen and select your slider input. You can then change the min and max values.

Note : It also works for colors for instance. In this case the RGB channels will get replaced by the factor value.