You can get some degree of 'fake' translucency in Terragen. In this case the default colour image has a value of 0.01 and the translucency(with no map) has a value of 250.
Ridiculous values but they work to some extent to make the guy seem not so solid. Of course, there'll be no shiny rainbowy bits but maybe other translucency/specular functions or images could approximate that, too...
[attachimg=#]