How to make transpaprent materials?

My decals and texures with transparency have a black background in Beamng. I tried png and dds, please help if anyone knows how to solve this.

Here's my texture:



And this is what it looks like in game:

 

You need to add an opacity map (I think)

 

Can you explain how to do that please?

 

If what you're working with is a mesh, it's a black and white map where the black areas are the transparent ones. You need to set it up in Blender then

 

Well, it's just a texture for a decal.