Hi,
I have a quick question regarding material instances and the resources it uses when attached to a BP.
So for instance (no pun intended) I create a texture for some pipes. I create parameters within the material editor which allows me to add dirt and scratches through an alpha channel or what not.
I then create a SM pipe and make it a Blue Print, within its construction parameters I create a material instance of the above material and configure it so I can adjust the alpha channel of the dirt, so basically I can drag the pipe into the editor and in the attributes add different degrees of dirt.
So my question is, if I had 20 of these pipes with each pipe having a different degree of dirt, does that mean the engine has loaded 20 versions of this texture? Or am I better just literally making a material instance and have maybe 4 instances of dirt that I can simply drag onto the pipes in the editor replacing the texture with the instance version of the texture.
I know instances are not complete new textures for the engine to load each time and its more efficient then actually having 4 versions of a texture, but what method above is better, or are material instances such low cost that its nothing to worry about ish.
Im just concerned that if I have many pipes running around my levels all with different material instances it could be costly?
Please advise 
Thanking you in advance.