most of the rifle baked all right, but almost none of the meshes of the rocket launcher or pistol worked. i tried the method of breaking the failed sections into new objects (P separate by selection), then highlighting them, then baking again, but the result was a complete failure. everything is just black.
Interesting, does it still take time to bake or does it error out? If it's still baking but turning up black, try to see if there are any hidden objects that could be overlapping them (high poly versions, cages, or whatnot). If so, turning off their camera icon in the outliner will fix the issue.
thanks for the quick reply. no errors, and the bake takes ages! in fact, it takes forever, as it keeps going round and round, doing the bake over and over. the result is always the same - about 1/3 is done, 2/3 isn't. that was in 2.79b. now trying it in very recent 2.79.6 to see if the same thing happens.
update: exactly the same thing happens on 2.79.6. i guess my file must be corrupted in some way.
That's a bummer. Please report it here! https://developer.blender.org/
I've noticed some memory leaks when it comes to baking, but haven't heard back from any developers about it.
i will report it.
i will also try making a very simple model with some bits of mesh that will cause occlusion and try that. my models are far simpler than the ones you have used, so it makes sense for me to try this. for instance, i need soon to create an imposing, large manor house door with suitable brass knobs and maybe a letter box. i also have to create a whole victorian-style study (complete with stuffed tiger) and a gun room, which will be a bit more challenging.
i might also try baking in 2.8 beta.