Hi,
regarding the sword scene, it is a geometry problem. Actually if you look at the sword you can see the error in the mesh...
In any case, a lot of people complain about softshadows, but no one takes the time to send us example files of those problems so that we can actually try to fix them or tell you how to do things.
I would like to remind you that you can always contact our technical support at : support@eovia.com and it is free ! (not like a lot of other companies). And we will look into the issues you are reporting and try to help you and try to make sure they do not occur in the next version of Carrara.
If you have problems with tech support, you can contact me directly at charles@eovia.com.
Regarding the GI, if you try to light a scene with hundreds of glowing objects, you are asking for trouble! I could probably get it to work but calculation time would be huge. Actually a radiosity algorithm would probably be better for that kind of scene.
If you want to use glowing objects, you need to make sure that there are not too many of them or it will not work. If they are really small it will cause problems too...
Increasing the number of photons will help detecting those small light sources...
In any case, we are working on those issues right now for carrara Studio 3 so now is the time to contact us and send us the files that are causing you problems ! I would really like to get the files you posted pictures for instance.
Thanks for your help
Charles