ec145/Models/instruments/overhead/overheadlight.xml

<PropertyList>
    <path>overheadlight.ac</path>
    
    <animation>
        <type>billboard</type>
        <object-name>floodhalo</object-name>
    </animation>

    <!-- halo on floodlight, visible only during night time -->
    <animation> 
      <type>select</type> 
      <object-name>floodhalo</object-name>
      <condition>
        <not>
          <equals>
            <property>/systems/electrical/outputs/floodlight</property>
            <value>0</value>
          </equals>
        </not>
        <equals>
          <property>sim/current-view/internal</property>
          <value>true</value>
        </equals>
        <greater-than>                
          <property>/sim/time/sun-angle-rad</property>
          <value>1.6</value>
        </greater-than>
     </condition>
    </animation>    
      
    <animation> 
      <type>material</type> 
      <object-name>floodhalo</object-name>
      <emission>
        <red>1</red>
        <green>1</green>
        <blue>1</blue>
      </emission>
      <ambient>
        <red>0</red>
        <green>0</green>
        <blue>0</blue>
      </ambient>      
      <specular>
        <red>0</red>
        <green>0</green>
        <blue>0</blue>
      </specular>
      <diffuse>
        <red>0</red>
        <green>0</green>
        <blue>0</blue>
      </diffuse>      
      <transparency>
          <alpha-prop>constants/zero</alpha-prop>
          <factor>1</factor>
          <offset>0.6</offset>      
      </transparency>      
      <shininess>0</shininess>
    </animation>    
</PropertyList>