Planar objects with opacity maps matteing out the fume smoke

[Rif]

Hey spencer , what renderer are you using ?

I v ran into similar things using Raytracers with Fume and Opacity maps.. its normal exceptions with Max atmospherics .. In Fr , their is in general tab something to uncheck about Atmospherics and Gbuffer extracts witch solved alot of my problemes with hold outs and RE extracts and etc..

If your using streight Scanline renderer , i think i m missunderstanding your post then and i think the best thing to do is to post either here or on cgfluids a simple scene similar to what you have and will take a look at it no prob

cheers,