Hi, this is the first time I've posted anything on here so I'm sorry if I've put this in the wrong place but I'm trying to create a Jbeam for a vehicle in blender (see picture below) but every time I try to export the file it just creates files for random objects I've used to make it. I want one big file.
Hmm, that probably is not your model. Anyway it looks to me that your origins are not at 0, 0, 0 you would need to apply location, rotation and scale, but also that is mesh side of things, not jbeam side of things. Jbeam is not much like mesh, it is lot more simplified with much more beams, you can't just export model to get jbeam, because jbeam is so different it needs to be made from scratch, each part then is own file which you then can combine to single file, but they usually need lot of editing too.
Ah, I see. The only thing I can tell you that could help is to duplicate all the meshes (just in case), selected them & then press Ctrl + J to join all the meshes into one (or atleast the ones you want). This may help, but may also mess up your meshes in Blender
Well, it did work partly at least I think you have had some mirror modifiers there, then when you joined pieces together, one you joined to hasn't had mirror modifier so one you joined in lost it's mirror modifier in process. Before joining you might need to apply mirror modifiers and it is important you work on spare copy as changes of such might not be reversible easily. You need control+n to get mirrored faces (odd dark blue ones) to be correct way around.
Should be in modifiers tab, same place where materials tab is etc. Hmm, I see, I have to wait 6 seconds before posting...
OK, I've fiddled about with it and it appears to have worked but I don't know if it has, I'm not sure if the entire model has been rendered or just part of it