Hatch styles are just CC3+ drawings. Very similar to symbol fill, but it uses an .fcw file instead of a symbol. You'll find all the existing ones in @Hatch Styles.

Hatch styles are not normal fills however, and only work with drawing tools. If you make a custom drawing tool, and set the outline to be an extra entity, you can pick the desired hatch style in the properties for it in the tool. The list here is just all the files in @Hatch Styles.

These hatch styles should be basic, simple drawings.

I know Ralf have done some work on hatch styles in some of the live videos. I'll update this post with links if I can identify them.

Here's one explanation:

I think we've all been there, starting new projects when we have this other one that is still waiting for us to complete it.

The issue here is with the wide lines. Unfortunately, symbol fills cannot have lines with a width other than 0, nor can they have solid filled polygons.

If you change the line width to 0, it should work, but that probably won't be the look you are after then.

You're probably better off making that as a png image instead and using it as a regular bitmap fill instead.

Keep in mind that the names of the fills doesn't mean anything, it is just a name. Just because that particular fill happens to be named "background" doesn't mean it is the fill that is used for the map background.

If you look at my screenshot below, I have used the List command on the background polygon. In the list output, you can see the fill is "P3B Parchment Background Bitmap", which you can then look up in the fill style dialog as I did in my screenshot.

As Steven chimed in above, this comes from Perspectives 3. (It can be a bit difficult to read from the fill style file name since it doesn't mention Perspectives int he path, but P3B means Perspectives 3, bitmap style B.)

Note that the file structure for CC3+ is exactly the same as for CC3, with one critical difference. While CC3 kept all the data files in it's installation directory along the actual program files, CC3+ instead puts all the data files in a separate directory, C:\ProgramData\Profantasy\CC3Plus by default, insteaf of the installation directory (C:\Program Files (x86)\Profantasy\CC3Plus). You'll find everything you used to find in the installation directory in the data directory.