add blank material files

valve/pbr/halflife.wad/+ELEV_DOWN/+ELEV_DOWN.mat

@@ -0,0 +1,16 @@
+
+{
+"for" "+0ELEV_DOWN"
+//"basecolor_map" "+0ELEV_DOWN.png"
+//"normal_map" "+0ELEV_DOWN_normal.png"
+//"metal_map" "+0ELEV_DOWN_metal.png"
+//"roughness_map" "+0ELEV_DOWN_roughness.png"
+}
+
+{
+"for" "+AELEV_DOWN"
+//"basecolor_map" "+AELEV_DOWN.png"
+//"normal_map" "+AELEV_DOWN_normal.png"
+//"metal_map" "+AELEV_DOWN_metal.png"
+//"roughness_map" "+AELEV_DOWN_roughness.png"
+}