Is there any way to edit a .shader file so that this happens but the other way around? I want to make it so that zooming out makes the province borders disappear (and maybe the state ones for full-zoom outs)

I have a map mod I'm still working on and it uses semi transparent province borders. They look great zoomed in but the border texture causes "pop-in" and "flashing" when moving the camera around zoomed out.

This module does not work in my game. When the perspective extends to the whole world, it will make the boundaries and rivers disappear; I tried to change the resolution and modify the zoom settings, but it still didn't work.

Alright, thanks for the help.

Theatrum Orbis Addon's border1.dds stands for a very thin provincial border. So borders between provinces virtually disappear and ones between countries still remain when zoom out.

You don't need this mod to do that. This mod removes all borders when zoom in. It can't remove them selectively.

I know where the folders for the mods are, but I don't see a border1.dds file. The files are mostly paint.net . I tried replacing the border1.pdn file in GMI with the Theatrum Orbis one but the only difference it made is changing the borders between provinces.

I made the changes that you explained to the other guy how to do (borders disappear when zoomed out). What I also would like is for the borders between each country (which i think is border5) to still remain, but the other borders disappear.

If you can find GMI folder, copy it in Documents/Paradox Interactive/Europa Universalis IV/mod. Then replace border1.dds with one from Theatrum Orbis Terrarum for 1.30 - Dynamic Borders Addon.
Because this process is a little complicated, you need some modding skills. You can find basic ones in EU4 Wiki.

I am using Graphical Map Improvements. I'm not sure where to find the vanilla folder so that I can replace with with border1 from GMI.

You can do that by replacing vanilla /map/terrain/border1.dds with another file. For example, you can get it from 'Theatrum Orbis Terrarum for 1.30 - Dynamic Borders Addon' mod.

Is there a way to keep the borders between countries?

Yes. It means height from the sea level. I have no idea about its unit.
This mod tweaks all borders include sea, areas, etc.
Note: You shouldn't remove suffix f. It means floating point number in programming languages.

Ok thanks. Just so I know, what does this 40.0f mean ? If I want to tweak other borders for example (sea, areas,etc). Is it height related ?

Thanks for your interest. You have to edit 2 lines to reverse the mod's function.
They're line 198 in /gfx/FX/border.shader and line 122 in /gfx/FX/strait.shader.
All you need is to reverse the signs of inequality. e.g. WATER_HEIGHT > 40.0f.
You can adjust the height where borders appear/disappear by changing the value 40.0f.
Good luck!

Thanks for your mod. Actually I am interested for the reverse ^^
I would like to see provinces borders when zooming in (i.e when managing troop movement) while they would disappear when zooming out (displaying only area borders, then when zooming out even more, only countrdy borders).
How could I edit that ?

Thanks so much.

nice work...

Thanks.

good idea