scattering media seems to be always and only illuminated by global 
light_sources, even if "global_lights off" is specified.

Also, Pov always gives a warning "no pigment type given" when using 
light_groups.

here a small scene to demonstrate it

#version 3.5;

global_settings
{
	assumed_gamma 1
	ambient_light 0
}

camera
{
	location <0,0,-5>
	look_at <0,0,0>
}

#macro light_marker(rad,col)
sphere
{
	0,1
	hollow
	pigment{color rgbt 1}
	interior
	{
		media
		{
			emission 1/rad*col
			density{spherical}
		}
	}
	scale rad
	
}
#end

light_source
{
	<1.5,1.5,-1>
	color rgb <1,0,0>
	looks_like{light_marker(.5,<1,0,0>)}
}

light_group
{ 
	
	light_source
	{
		<-1.5,1.5,-1>
		color rgb <0,0,1>
		looks_like{light_marker(.5,<0,0,1>)}
	}
	
	sphere
	{
		<0,0,0>,.5
		hollow
		texture{pigment{color rgbt 1}}
		interior
		{
			media
			{
				scattering{1,color rgb 10}
				intervals 3
			}
		}
	}
	
	global_lights off
}

Post a reply to this message