http://www.3d1.org/
It has affiliations with the 3DState engine (probably written in it too). Don't know if it's any good, but it has a nice feature list. I couldn't find CSG on the list but I did see 'cutting' which might be the same thing.
In the e-mail I got sent it said that its 'free for non-commercial use', but didn't mention how much it costs otherwise. Have a look anyway... ;)
It has affiliations with the 3DState engine (probably written in it too). Don't know if it's any good, but it has a nice feature list. I couldn't find CSG on the list but I did see 'cutting' which might be the same thing.
In the e-mail I got sent it said that its 'free for non-commercial use', but didn't mention how much it costs otherwise. Have a look anyway... ;)