I am very grateful for all your input guys, very helpful indeed. Though I didn't get a chance to read through the Poseray manual, I saved it as pdf, so will later.
@paq: the problem might be that I still work in LW 9, and that doesn't export obj's set up in layers, e.g. Only one layer exports. If I put it all on one layer it works though. I still have to experiment more, but I am kind of glued to my workflow, and it takes time to deviate and experiment. LW 9 doesn't have such a fancy exporter menu, it just runs. So I guess, Kadri is right. And yes, that's why I use P.
@Jochen: In LW I make a part, like a beam, and UV it. If I want specific parts to be oriented differently, I select the polys, cut and paste, or unweld, and move it around, or remap that part of the part. Then what I usually do is merge points.
But I also cut of parts of finished beams off in the normal viewports, and paste them to another layer temporarily, and move them around for additional beams (under eaves for instance), so I don't have to UVmap them separately. Then I select them randomly or one by one and move them around or rotate 180º in UV space, so they show different parts of one texuremap.
Probably not the right way, as exporting this lot often gets the UV map torn.
Anyway, I haven't been modeling that long, so it's still a big learning process for me, and thanks again for all the info guys!