I'm using maya, and if I want to render just a single segment of a scene, I just create a camera at (0,0,0) with the aim pointed at the object (0,0,1), and I don't have to adjust anything else, the object is properly positioned.
Also, I noticed that I get best results when I don't touch any of the default settings in ZBM2OBJ, e.g. nclip: 0.01, fclip: 10.0, FOV: 75, MAX: 1. If I try to adjust them to match the scene from the *.SET file, I get badly formed OBJs. Is this the intended behaviour?
so the nclip and fclip currently don't work properly, they just basically scale the mesh but the values are not correct, i usually use the default values. max z is also dependent on the nclip and fclip values so if you increase them you should increase max z as well.
the fov on the other hand is very important you should use the exact number from the .set files, if you don't the model will appear stretched. you can verify that the fov is correct if you look at the mesh from the camera. if you set the same fov and aspect ratio on the camera the frame should be filled completely.
when you import the mesh the orientation isn't correct and it assumes that the camera is positioned and (0,0,0) and pointing at the object. to correct that you should move and rotate the camera and mesh together, in blender you can make the mesh the child of the camera so they transform together, i assume you can do the same in maya. so if you move the camera to the position from the .set file and point it at the interest point they should be set correctly.
here you can see that the walls and floor line up correctly
also the values in the .set files are very small so i multiply them by 10 so i don't have to scale the models too much.
I haven't really looked at the *.zbm structure, but if the *.zbms are just pixeldata (e.g. RGB values for each pixel), then there's only so much we can do with the for example 640x480 images. If however, it is actually differently stored, then possibly we could upscale that data to avoid jagged edges. (I find it unlikely that the *.zbms are stored otherwise though)
i haven't tried to open the *.zbms myself but the way different software read them is different, here you can see the rgb channels of the images i got from scummrev and grimedi.