Set line width in COLLADA for viewing in Google Earth

I can set up 3D lines in a COLLADA .dae file and view them in Google Earth, but they are really thin and very hard to see over Colorado. How can I set the line width to something other than the default of 1 (meter?)? I have located the line_width tag in the COLLADA documentation, but it does not seem to do anything no matter where I put it.

Here is my .dae file Lines-blue.dae.

<?xml version="1.0"?>
<COLLADA xmlns="http://www.collada.org/2005/11/COLLADASchema" version="1.4.1">
  <asset>
    <contributor>
      <author>Carl Drews</author>
      <authoring_tool>Assimp Collada Exporter</authoring_tool>
    </contributor>
    <created>2000-01-01T23:59:59</created>
    <modified>2000-01-01T23:59:59</modified>
    <unit name="meter" meter="1" />
    <up_axis>Z_UP</up_axis>
  </asset>
  <library_effects>
    <effect id="m0DefaultMaterial-fx" name="m0DefaultMaterial">
      <profile_COMMON>
        <technique sid="standard">
          <phong>
            <emission>
              <color sid="emission">0   0   0   1</color>
            </emission>
            <ambient>
              <color sid="ambient">0.05   0.05   0.05   1</color>
            </ambient>
            <diffuse>
              <color sid="diffuse">0   0   1   1</color>
            </diffuse>
            <specular>
              <color sid="specular">0   0   0   1</color>
            </specular>
            <shininess>
              <float sid="shininess">16</float>
            </shininess>
            <reflective>
              <color sid="reflective">0   0   0   0</color>
            </reflective>
            <transparency>
               <float sid="transparency">0.5</float>
            </transparency>
          </phong>
        </technique>
	<extra>
          <technique profile="GOOGLEEARTH">
            <double_sided>1</double_sided>
            **<line_width>1200.0</line_width>**
          </technique>
	</extra>
      </profile_COMMON>
    </effect>
  </library_effects>
  <library_materials>
    <material id="m0DefaultMaterial" name="m0DefaultMaterial">
      <instance_effect url="#m0DefaultMaterial-fx"/>
    </material>
  </library_materials>
  <library_geometries>
    <geometry id="meshId0" name="meshId0_name" >
      <mesh>
        <source id="meshId0-positions" name="meshId0-positions">
          <float_array id="meshId0-positions-array" count="36">
		  0 0 0
		  12000 0 0
		  6000 6000 6000
		  
		  12000 0 0
		  12000 12000 0
		  6000 6000 6000
		  
		  12000 12000 0
		  0 12000 0
		  6000 6000 6000
		  
		  0 12000 0
		  0 0 0
		  6000 6000 6000
		  </float_array>
          <technique_common>
            <accessor count="12" offset="0" source="#meshId0-positions-array" stride="3">
              <param name="X" type="float" />
              <param name="Y" type="float" />
              <param name="Z" type="float" />
            </accessor>
          </technique_common>
        </source>
        <source id="meshId0-normals" name="meshId0-normals">
          <float_array id="meshId0-normals-array" count="36">
		  0 -0.5 0.5
		  0 -0.5 0.5
		  0 -0.5 0.5
		  
		  -0.5 0 0.5
		  -0.5 0 0.5
		  -0.5 0 0.5
		  
		  0 0.5 0.5
		  0 0.5 0.5
		  0 0.5 0.5
		  
		  -0.5 0 0.5
		  -0.5 0 0.5
		  -0.5 0 0.5
		  </float_array>
          <technique_common>
            <accessor count="12" offset="0" source="#meshId0-normals-array" stride="3">
              <param name="X" type="float" />
              <param name="Y" type="float" />
              <param name="Z" type="float" />
            </accessor>
          </technique_common>
        </source>
        <vertices id="meshId0-vertices">
          <input semantic="POSITION" source="#meshId0-positions" />
          <input semantic="NORMAL" source="#meshId0-normals" />
        </vertices>
        <lines count="4" material="theresonlyone">
          <input offset="0" semantic="VERTEX" source="#meshId0-vertices" />
          <vcount>3 3 3 3</vcount>
          <p>0 1 2
		  3 4 5
		  6 7 8
		  9 10 11
		  </p>
        </lines>
      </mesh>
    </geometry>
  </library_geometries>
  <library_visual_scenes>
    <visual_scene id="myScene" name="myScene">
      <node id="STL_BINARY" name="STL_BINARY">
        <matrix>1 0 0 0
		        0 1 0 0
				0 0 1 0
				0 0 0 1</matrix>
        <instance_geometry url="#meshId0">
          <bind_material>
            <technique_common>
              <instance_material symbol="theresonlyone" target="#m0DefaultMaterial"/>
            </technique_common>
          </bind_material>
        </instance_geometry>
      </node>
    </visual_scene>
  </library_visual_scenes>
  <scene>
    <instance_visual_scene url="#myScene" />
  </scene>
</COLLADA>

Here is the KML fragment that includes the COLLADA Model:

<Style id="WideLine">
  <LineStyle>
    <width>100</width>
  </LineStyle>
</Style>

<Placemark>
  <name>Experimental white lines floating over Boulder.</name>
  <description>Model created by Carl Drews - November 18, 2022.</description>

  <Camera>
    <longitude>-105.1000</longitude>
    <latitude> 40.0650</latitude>
    <altitude>2000</altitude>
    <tilt>90.00</tilt>
    <heading>-90.00</heading>
  </Camera>

  <Style id="default">
    <styleUrl>#WideLine</styleUrl>
  </Style>

  <Model id="model_7">
    <altitudeMode>relativeToGround</altitudeMode>
    <Location>
      <longitude>-104.9000</longitude>
      <latitude> 39.7000</latitude>
      <altitude>1000</altitude>
    </Location>
    <Orientation>
      <heading>0</heading>
      <tilt>0</tilt>
      <roll>0</roll>
    </Orientation>
    <Scale>
      <x>1</x>
      <y>1</y>
      <z>1</z>
    </Scale>
  <Link>
    <href>Lines-blue.dae</href>
  </Link>
  </Model>
  <TimeSpan>
    <begin>2021-04-09T00:00:00Z</begin>
    <end>2021-04-11T00:00:00Z</end>
  </TimeSpan>
</Placemark>

These lines in 3D space are supposed to trace the contours of 3D isosurfaces that I have already created with COLLADA and displayed with Google Earth. But the lines won’t show up unless they are thicker or wider. I could create lines in pure KML (no .dae) but I don’t think they will lay down on my isosurfaces accurately enough.

Thank you for any assistance you can provide.

Here is a screen shot to clarify. The thin blue lines run from roughly Glendale to Buckley AFB and then on to Rocky Mountain Arsenal.

Hmm, I don’t know a lot about COLLADA and Google Earth (GE), but it looks like you are using a GE specific extension for the line width - assuming that is the way to do that it feels like a bug in the GE renderer. Line width is often specified in pixels, have you tried some values in the 1-10 range?
Also, KML has support for line width (no idea if it works though :wink: ) - can you use that instead of COLLADA?