i've been using the multi-pass render pluging (with 6.5), its cool and i've been following the tutorial from Matt Estela here: http://www.tokeru.com/twiki/bin/view/Main/RenderPassTutorial
a minor problem, unless i'm missing something, i think a reflection pass MUST inlcude both specular and shadows anyway, otherwise the shadows and specular highlights are missing from reflections? (like in a mirror, its really obvious they're missing ;) ). anyway that's not a major issue because i can set that up and its reasonably quick, and also get a seperate non-reflection shadow-pass.
one MAJOR problem: as soon as you have more than one reflective object in a scene, and they both have to reflect each other, then you have to configure a seperate reflection pass for every reflective object, otherwise their diffuse color's won't show up in each other's reflections... in the tutorial diffuse or color is turned to black to allow only the reflecion to show up, so one object's reflection will be missing the other's diffuse color. playing with primary visibility aint an option, it has to be on for all reflective objects, otherwise they won't reflect :( .
the same with ambient occlusion... i've been using the mib_amb_occlusion shader, but i'm not sure how to get the AO effect to show up in a reflection pass??
for architecture animations that need realistic reflections is the whole multi-pass thing worthless.?? i hope not 'cause its a nice speedy rendering method - any help would be cool :)
EDIT: OK, i figured out problem 1 with reflection of diffuse, all reflecitve objects can be rendered at once but they have to have diffuse color enabled as well, and they can just be invisilble in the diffuse pass.
i think the same would be true for bump and transparency surfaces... being rendered along with reflections. bump requires spec to be visilble doesn't it? (not sure on that). if not then i could get away with it not being visible in reflections... but not transparency ;)