Hi! I've got a small issue with fill on my slab. Specifically - I can do nothing about it. I tried to change it (fit it), or do anything about it but it just won't change. Parameters shown in a screenshot apply to slab on the same picture. Am I doing something wrong? Is something disabled? Please, help
Your screen shot shows the dialog box for the Slab Settings > Floor Plan and Section for the Cover Fill, which is seen in the 2D view. The Slab's section is set by the Geometry and Positioning > Cut Fill (Insulation - Mineral Soft in your case). So to change the Slab's Section Fill Type, use the Geometry and Positioning setting. In the Floor Plan and Section panel there is the Cut Surfaces subpanel where the Section Pens can be changed.
If you want the fill to fit, it's better if you use composites (instead of a basic structure). That way you can set the building material fill orientation to "Fit to skin".
The "Insulation - Mineral Soft" you are using already has this setting, just use it with a composite structure.
Well... Works like charm! So, as I understand, even if I want to make a single layer slab it's better to make it as composite so fill will fit, right? Because making it the other way will mess its look in section?
Depends on the fill. In your example where there is a fill that needs to fill the space to look correct, use the Composite. But there are many other fills, like concrete, where the fill origin and width does not matter. Basic slabs can be any thickness, for the Composites you would need to create a separate Composite for each thickness.