Consider the following region:
Vol1 = Parallelepiped[{-4.75, -1.25,
14.5}, {{3.35, 0, 0}, {0, 2.5, 0}, {0, 0, 12}}];
Vol2 = Parallelepiped[{-4.75, -1.25,
14.5 + 12}, {{2.5, 0, 0}, {0, 2.5, 0}, {0, 0, 7}}];
Vol = RegionUnion[Vol1, Vol2];
It looks like
PlotVol =
Region[Style[Vol, Blue, Opacity[0.2], EdgeForm[{Thick, Blue}]],
BoxRatios -> {1, 1, 10}, Boxed -> True, Axes -> True]
Could you please tell me how to get rid of the contour of their boundaries in the plot (shown in red)?