Inkscape - transparent fill, but still occlude paths below it

Question

I'm doing line art in Inkscape. For the sake of saneness, I need the fill of a path to occlude paths beneath it, so I just fill everything with white.

However, while exporting to a bitmap, I don't want the fills to actually be white - I just want to export the lines, with no fills.

---

Here's a example:

With fills:

no fills:

what I want:

---

I know I can replace the white with transparent in other software, but often the results are not perfect (antialiasing results in white fringing).

I also know this can be done with boolean operations on the paths, but it's not really feasible for complex work, and destroys information in the process.

Answer 1

You cannot have a background color at the same time transparent and not transparent.

In your example, you have two objects layered one on each other, and a possible background, let's say a, b and bg:

When you remove the fill of the top object (b, in the example), you see directly a portion of the other object, and precisely the intersection of a and b:

To get rid of the intersection and see directly the background, the only way is modify the lower object using boolean operations:

Answer 2

A workaround, if boolean operations is not an option, would be:

1. Export your drawing as png, including undesired white surfaces (but with correct black lines);
2. Open your png image in Gimp (or Photoshop), and use Color > Color to Alpha, select white as the color to become transparent. Export to png.