How do I edit .dmx files on the Steam version of Black Mesa?

I have bought the Steam version of the game and I wanted to do some modifications to the weapons but the weapon files appears to be in .dmx format. When I try to open them with notepad I see no text inside although they have a file size. Can someone tell me how I open and modify them? It should be possible because in the workshop I have seen other mods that seems to alter the same files. If anyone has any ideas or suggestion I would appreciate it a lot (also, if there’s a better place to post this question on this forum please tell me where to do so).

Extract them and open them with a text editor, should work fine!

I’ve tried now and I can’t extract any further files once they are in .dmx format. What exactly did you mean by that? Which vpk-files were I meant to extract them from?

Which text editor should I use then? I tried Wordpad and Notepad but the files appear empty.

Edit: I have now found that the .dmx files of other peoples mods work as they should. For example, if I download the “More accurate shotgun” mod and open it, then the weapon_shotgun dmx-file inside will work perfectly and the text can be seen. But if I extract the same files from the Black Mesa I have installed on my computer, then those files will appear completely empty even though they have a file size. Does anyone know why that is the case?

Founded in 2004, Leakfree.org became one of the first online communities dedicated to Valve’s Source engine development. It is more famously known for the formation of Black Mesa: Source under the 'Leakfree Modification Team' handle in September 2004.