diff --git a/materials-dds.xml b/materials-dds.xml
index 30ec470d8..139ba819b 100644
--- a/materials-dds.xml
+++ b/materials-dds.xml
@@ -904,9 +904,9 @@ Shared parameters for various materials.
     </condition>
     <name>BuiltUpCover</name>
     <name>Urban</name>
-    <name>Construction</name>
+    <!--<name>Construction</name>
     <name>Industrial</name>
-    <name>Port</name>
+    <name>Port</name>-->
     <effect>Effects/urban</effect>
     <texture-set>
       <texture>Terrain/city1.png</texture>
@@ -993,6 +993,99 @@ Shared parameters for various materials.
     <tree-width-m>15.0</tree-width-m>
   </material>
 
+  <material>
+    <condition>
+      <and>
+        <equals>
+          <property>sim/startup/season</property>
+          <value>summer</value>
+        </equals>
+        <property>sim/rendering/urban-shader</property>
+      </and>
+    </condition>
+    <!--<name>BuiltUpCover</name>
+    <name>Urban</name>-->
+    <name>Construction</name>
+    <name>Industrial</name>
+    <name>Port</name>
+    <name>Transport</name>
+    <effect>Effects/urban</effect>
+    <texture-set>
+      <texture>Terrain/city1.png</texture>
+      <texture n="2">Terrain/city1-relief-light.png</texture>
+    </texture-set>
+    <texture-set>
+      <texture>Terrain/city2.png</texture>
+      <texture n="2">Terrain/city2-relief-light.png</texture>
+    </texture-set>
+    <!--
+  <texture-set>
+   <texture>Terrain/city3.png</texture>
+   <texture n="2">Terrain/city3-relief-light.png</texture>
+  </texture-set>
+-->
+    <xsize>1000</xsize>
+    <ysize>1000</ysize>
+    <light-coverage>100000.0</light-coverage>
+    <emissive>
+      <r>0.05</r>
+      <g>0.05</g>
+      <b>0.02</b>
+      <a>1.0</a>
+    </emissive>
+    <object-group>
+      <range-m>10000</range-m>
+      <object>
+        <path>Models/Buildings/oil-tanks.ac</path>
+        <coverage-m2>10000000</coverage-m2>
+        <heading-type>random</heading-type>
+      </object>
+      <object>
+        <path>Models/Buildings/factory.ac</path>
+        <coverage-m2>4000000</coverage-m2>
+        <heading-type>random</heading-type>
+      </object>
+      <object>
+        <path>Models/Industrial/Zone-Indus-long-ba.ac</path>
+        <coverage-m2>4000000</coverage-m2>
+        <heading-type>random</heading-type>
+      </object>
+      <object>
+        <path>Models/Industrial/Zone-Indus-ba.ac</path>
+        <coverage-m2>4000000</coverage-m2>
+        <heading-type>random</heading-type>
+      </object>
+    </object-group>
+    <object-group>
+      <object>
+        <path>Models/Commercial/small-glass-office-building.ac</path>
+        <path>Models/Buildings/medium-glass-office-building.ac</path>
+        <path>Models/Buildings/small-modern-office.ac</path>
+        <path>Models/Buildings/small-office.ac</path>
+        <coverage-m2>500000</coverage-m2>
+        <heading-type>random</heading-type>
+      </object>
+      <object>
+        <path>Models/Buildings/water-tower.ac</path>
+        <coverage-m2>100000000</coverage-m2>
+        <heading-type>random</heading-type>
+      </object>
+      <object>
+        <path>Models/Commercial/Petrolstation1.ac</path>
+        <coverage-m2>10000000</coverage-m2>
+        <heading-type>random</heading-type>
+      </object>
+    </object-group>
+    <wood-coverage>250000.0</wood-coverage>
+    <wood-size>5000.0</wood-size>
+    <tree-density>2000.0</tree-density>
+    <tree-texture>Textures.high/Trees/mixed-summer.dds</tree-texture>
+    <tree-varieties>8</tree-varieties>
+    <tree-range-m alias="/params/forest/tree-range-m"/>
+    <tree-height-m>25.0</tree-height-m>
+    <tree-width-m>15.0</tree-width-m>
+  </material>
+
   <material>
     <condition>
       <equals>
@@ -1005,9 +1098,6 @@ Shared parameters for various materials.
     </condition>
     <name>BuiltUpCover</name>
     <name>Urban</name>
-    <name>Construction</name>
-    <name>Industrial</name>
-    <name>Port</name>
     <effect>Effects/transition-base-dirt</effect>
     <texture-set>
       <texture>Terrain/city1.png</texture>
@@ -1034,11 +1124,6 @@ Shared parameters for various materials.
     </emissive>
     <object-group>
       <range-m>10000</range-m>
-      <object>
-        <path>Models/Buildings/oil-tanks.ac</path>
-        <coverage-m2>10000000</coverage-m2>
-        <heading-type>random</heading-type>
-      </object>
       <object>
         <path>Models/Buildings/big-apartment.ac</path>
         <coverage-m2>10000000</coverage-m2>
@@ -1094,6 +1179,97 @@ Shared parameters for various materials.
     <tree-width-m>15.0</tree-width-m>
   </material>
 
+  <material>
+    <condition>
+      <equals>
+        <property>sim/startup/season</property>
+        <value>summer</value>
+      </equals>
+      <not>
+        <property>sim/rendering/urban-shader</property>
+      </not>
+    </condition>
+    <name>Construction</name>
+    <name>Industrial</name>
+    <name>Port</name>
+    <name>Transport</name>
+    <effect>Effects/transition-base-dirt</effect>
+    <texture-set>
+      <texture>Terrain/city1.png</texture>
+      <texture n="4">Terrain.winter/builtup.png</texture>
+    </texture-set>
+    <texture-set>
+      <texture>Terrain/city2.png</texture>
+      <texture n="4">Terrain.winter/builtup.png</texture>
+    </texture-set>
+    <!--
+  <texture-set>
+   <texture>Terrain/city3.png</texture>
+   <texture n="2">Terrain/city3-relief-light.png</texture>
+  </texture-set>
+-->
+    <xsize>1000</xsize>
+    <ysize>1000</ysize>
+    <light-coverage>100000.0</light-coverage>
+    <emissive>
+      <r>0.05</r>
+      <g>0.05</g>
+      <b>0.02</b>
+      <a>1.0</a>
+    </emissive>
+    <object-group>
+      <range-m>10000</range-m>
+      <object>
+        <path>Models/Buildings/oil-tanks.ac</path>
+        <coverage-m2>10000000</coverage-m2>
+        <heading-type>random</heading-type>
+      </object>
+      <object>
+        <path>Models/Buildings/factory.ac</path>
+        <coverage-m2>4000000</coverage-m2>
+        <heading-type>random</heading-type>
+      </object>
+      <object>
+        <path>Models/Industrial/Zone-Indus-long-ba.ac</path>
+        <coverage-m2>4000000</coverage-m2>
+        <heading-type>random</heading-type>
+      </object>
+      <object>
+        <path>Models/Industrial/Zone-Indus-ba.ac</path>
+        <coverage-m2>4000000</coverage-m2>
+        <heading-type>random</heading-type>
+      </object>
+    </object-group>
+    <object-group>
+      <object>
+        <path>Models/Commercial/small-glass-office-building.ac</path>
+        <path>Models/Buildings/medium-glass-office-building.ac</path>
+        <path>Models/Buildings/small-modern-office.ac</path>
+        <path>Models/Buildings/small-office.ac</path>
+        <coverage-m2>500000</coverage-m2>
+        <heading-type>random</heading-type>
+      </object>
+      <object>
+        <path>Models/Buildings/water-tower.ac</path>
+        <coverage-m2>100000000</coverage-m2>
+        <heading-type>random</heading-type>
+      </object>
+      <object>
+        <path>Models/Commercial/Petrolstation1.ac</path>
+        <coverage-m2>10000000</coverage-m2>
+        <heading-type>random</heading-type>
+      </object>
+    </object-group>
+    <wood-coverage>250000.0</wood-coverage>
+    <wood-size>5000.0</wood-size>
+    <tree-density>2000.0</tree-density>
+    <tree-texture>Textures.high/Trees/mixed-summer.dds</tree-texture>
+    <tree-varieties>8</tree-varieties>
+    <tree-range-m alias="/params/forest/tree-range-m"/>
+    <tree-height-m>25.0</tree-height-m>
+    <tree-width-m>15.0</tree-width-m>
+  </material>
+
   <material>
     <condition>
       <equals>
@@ -1997,9 +2173,9 @@ Shared parameters for various materials.
     </condition>
     <name>BuiltUpCover</name>
     <name>Urban</name>
-    <name>Construction</name>
+    <!--<name>Construction</name>
     <name>Industrial</name>
-    <name>Port</name>
+    <name>Port</name>-->
     <effect>Effects/urban</effect>
     <texture-set>
       <texture>Terrain/city1.png</texture>
@@ -2086,6 +2262,96 @@ Shared parameters for various materials.
     <tree-width-m>15.0</tree-width-m>
   </material>
 
+  <material>
+    <condition>
+      <equals>
+        <property>sim/startup/season</property>
+        <value>winter</value>
+      </equals>
+    </condition>
+    <!--<name>BuiltUpCover</name>
+    <name>Urban</name>-->
+    <name>Construction</name>
+    <name>Industrial</name>
+    <name>Port</name>
+    <name>Transport</name>
+    <effect>Effects/urban</effect>
+    <texture-set>
+      <texture>Terrain/city1.png</texture>
+      <texture n="2">Terrain/city1-relief-light.png</texture>
+    </texture-set>
+    <texture-set>
+      <texture>Terrain/city2.png</texture>
+      <texture n="2">Terrain/city2-relief-light.png</texture>
+    </texture-set>
+    <!--
+  <texture-set>
+   <texture>Terrain/city3.png</texture>
+   <texture n="2">Terrain/city3-relief-light.png</texture>
+  </texture-set>
+-->
+    <xsize>1000</xsize>
+    <ysize>1000</ysize>
+    <light-coverage>100000.0</light-coverage>
+    <emissive>
+      <r>0.05</r>
+      <g>0.05</g>
+      <b>0.02</b>
+      <a>1.0</a>
+    </emissive>
+    <object-group>
+      <range-m>10000</range-m>
+      <object>
+        <path>Models/Buildings/oil-tanks.ac</path>
+        <coverage-m2>10000000</coverage-m2>
+        <heading-type>random</heading-type>
+      </object>
+      <object>
+        <path>Models/Buildings/factory.ac</path>
+        <coverage-m2>4000000</coverage-m2>
+        <heading-type>random</heading-type>
+      </object>
+      <object>
+        <path>Models/Industrial/Zone-Indus-long-ba.ac</path>
+        <coverage-m2>4000000</coverage-m2>
+        <heading-type>random</heading-type>
+      </object>
+      <object>
+        <path>Models/Industrial/Zone-Indus-ba.ac</path>
+        <coverage-m2>4000000</coverage-m2>
+        <heading-type>random</heading-type>
+      </object>
+    </object-group>
+    <object-group>
+      <object>
+        <path>Models/Commercial/small-glass-office-building.ac</path>
+        <path>Models/Buildings/medium-glass-office-building.ac</path>
+        <path>Models/Buildings/small-modern-office.ac</path>
+        <path>Models/Buildings/small-office.ac</path>
+        <coverage-m2>500000</coverage-m2>
+        <heading-type>random</heading-type>
+      </object>
+      <object>
+        <path>Models/Buildings/water-tower.ac</path>
+        <coverage-m2>100000000</coverage-m2>
+        <heading-type>random</heading-type>
+      </object>
+      <object>
+        <path>Models/Commercial/Petrolstation1.ac</path>
+        <coverage-m2>10000000</coverage-m2>
+        <heading-type>random</heading-type>
+      </object>
+    </object-group>
+    <wood-coverage>250000.0</wood-coverage>
+    <wood-size>5000.0</wood-size>
+    <tree-density>2000.0</tree-density>
+    <tree-texture>Textures.high/Trees/mixed-winter.png</tree-texture>
+    <tree-varieties>8</tree-varieties>
+    <tree-range-m alias="/params/forest/tree-range-m"/>
+    <tree-height-m>25.0</tree-height-m>
+    <tree-width-m>15.0</tree-width-m>
+  </material>
+
   <material>
     <condition>
       <equals>
@@ -2963,7 +3229,7 @@ Shared parameters for various materials.
 
   <material>
     <name>Railroad</name>
-    <name>Transport</name>
+    <!--<name>Transport</name>-->
     <texture>Terrain/gravel.png</texture>
     <xsize>400</xsize>
     <ysize>400</ysize>