we are all awaiting for emissive materials, that are not available until the next beta (we hope!).
in the meantime...sketchup+photoshop
listen: by the way, regardless to shape,refraction,or texture what is an emissive material? it's a shape in render that is overexposed (MUCH overexposed) with an hidden light binded to it.
note: it's overexposed so regardless to the material color, it appears white or bright colored
note #2: it's shining so regardless to the material color, it shines like one or more tiny spotlights with the same color placed in a precise geometry.
therefore:
how to:
1)draw a shape whatever you like in sketchup (in my case a tube light)
2)put many separated spotlights in this shape (e.g. a row of tiny spotlights for a tube)
3)set aperture (0-180°) power and color to match the tube light color until you have the desired lighting results (don't forget to set shadow softness until they all shine like a single light!)
4)render
5)edit image in photoshop and select the shape with magic wand or lazo or poligonal lazo
[or pixel by pixel if you have so much time :lol: :lol: ]
6)in this selection edit-image-adjustments-exposure or edit-image-adjustment-brightness/contrast until the shape shines bright
7)in the same selection edit-image-adjustments-variations or edit-image-adjustments-fotofilter to make the light color to match projected light color.
8)close photoshop
voilà!
(remember that if you have more than one tube light you can save each selection with name such as light01 etc. to make this procedure easier for later adjustments)
it worked good for me.
p.s. if you're looking for a much more easy way (pherhaps inside render[in]

) it is not available at the moment