add blank material files

gearbox/pbr/models/w_backpack.mdl/w_backpack.mdl.mat

@@ -0,0 +1,16 @@
+
+{
+"for" "#models/w_backpack/bullet.mdl"
+//"basecolor_map" "bullet.png"
+//"normal_map" "bullet_normal.png"
+//"metal_map" "bullet_metal.png"
+//"roughness_map" "bullet_roughness.png"
+}
+
+{
+"for" "#models/w_backpack/Chrome(yellow).mdl"
+//"basecolor_map" "Chrome(yellow).png"
+//"normal_map" "Chrome(yellow)_normal.png"
+//"metal_map" "Chrome(yellow)_metal.png"
+//"roughness_map" "Chrome(yellow)_roughness.png"
+}