diff --git a/mods/CORE/voxelibre/init.lua b/mods/CORE/voxelibre/init.lua
index 6ac470d7d..9629a3110 100644
--- a/mods/CORE/voxelibre/init.lua
+++ b/mods/CORE/voxelibre/init.lua
@@ -62,6 +62,20 @@ local function set_description(mod_name, identifier, definitions)
     end
 end
 
+local function set_groups(definitions)
+    if definitions.walkable == false then
+       definitions.groups.solidity = 0
+    else
+        definitions.groups.solidity = 1
+    end
+
+    if not definitions.drawtype and not definitions.groups.opacity then
+        definitions.groups.opacity = 1
+    else
+        definitions.groups.opacity = 0
+    end
+end
+
 local function set_images(mod_name, identifier, definitions)
     local base_image_name = mod_name.."_"..identifier..".png"
 
@@ -118,6 +132,7 @@ function voxelibre.register_block(identifier, definitions)
     end
 
     set_description(mod_name, identifier, definitions)
+    set_groups(definitions)
     set_images(mod_name, identifier, definitions)
     set_tiles(mod_name, identifier, definitions)
 
diff --git a/mods/blocks/building/structural.lua b/mods/blocks/building/structural.lua
index 8c5115b4f..715766736 100644
--- a/mods/blocks/building/structural.lua
+++ b/mods/blocks/building/structural.lua
@@ -21,17 +21,17 @@ local commondefs = {
 }
 
 local planks = {
-    ["acacia"]   = {groups = commondefs.flammable_planks_groups},
-    ["bamboo"]   = {groups = commondefs.flammable_planks_groups},
-    ["birch"]    = {groups = commondefs.flammable_planks_groups},
-    ["cherry"]   = {groups = commondefs.flammable_planks_groups},
-    ["crimson"]  = {},
+    ["acacia"] = {groups = commondefs.flammable_planks_groups},
+    ["bamboo"] = {groups = commondefs.flammable_planks_groups},
+    ["birch"] = {groups = commondefs.flammable_planks_groups},
+    ["cherry"] = {groups = commondefs.flammable_planks_groups},
+    ["crimson"] = {},
     ["dark_oak"] = {groups = commondefs.flammable_planks_groups},
-    ["jungle"]   = {groups = commondefs.flammable_planks_groups},
+    ["jungle"] = {groups = commondefs.flammable_planks_groups},
     ["mangrove"] = {groups = commondefs.flammable_planks_groups},
-    ["oak"]      = {groups = commondefs.flammable_planks_groups},
-    ["spruce"]   = {groups = commondefs.flammable_planks_groups},
-    ["warped"]   = {}
+    ["oak"] = {groups = commondefs.flammable_planks_groups},
+    ["spruce"] = {groups = commondefs.flammable_planks_groups},
+    ["warped"] = {}
 }
 
 for _, color in pairs(voxelibre.colors) do