Cornell Box on White Background

Skybox is commented.

            <babylon extends="minimal">
              <!-- Ground that receives shadows -->
              <ground receive-shadows="true"></ground>
              <!-- Default skybox
                     <model url="">
              <!-- enable antialiasing -->
              <engine antialiasing="true"></engine>
              <!-- camera configuration -->
                <!-- add camera behaviors -->
                  <!-- enable default auto-rotate behavior -->
                  <auto-rotate type="0"></auto-rotate>
                  <!-- enable and configure the framing behavior -->
                  <framing type="2" zoom-on-bounding-info="true" zoom-stops-animation="false"></framing>
                  <!-- enable default bouncing behavior -->
                  <bouncing type="1"></bouncing>
              <position x="3" y="3" z="3"></position>
                <clear-color r="1" g="1" b="1"></clear-color>

You may play with clear-color parameter (here – white color).