Darkmatter 2 may not be used with other Tools than DarkBasic, as far as I know.
I've just bought the DakMatter 1&2 model packs and I can't see anything in the copyright that explicitly limits the use of DM 2 to DarkBasic users. Although DB users are specifically mentioned in the copyright notice it doesn't say they are the only DM 2 purchasers who can make use of the models.
[EDIT]
Actually, after reading the copyright notice again, this has me a bit worried now. I'm wondering if I've wasted my money on these models.
[/EDIT]
Copyright text:-
Copyright
All models Copyright (c) Geo-metricks 2003. All rights reserved.
All 3D models included in the Dark Basic Model Pack library are non exclusive (Geo-metricks retains ownership and Copyright)
Dark Basic Users (End Users) are not authorized to :
Separately sell, re-sell, sell as, duplicate, collate, distribute, publish, represent - for re-sale or free objects, any original Geo-metricks 3D model or any derivative thereof, in any known digital format, by any means whatsoever, invented or yet to be invented, when the Geo-metricks models are the product itself e.g. 3d Clipart, 3D digital stock libraries.
Dark Basic Users (End Users) are however authorized to distribute or sell (royalty free) any Dark Basic application that contains the said models or derivatives in the .x file format only.