Hey: i'm quite confused by the contentManager of the XNA. if i want to load some thing from file , i have to generate the .xnb file which cost me some time. Suppose i want to load a scene which contains fifty models in an editor, i have to generate them each , and then load .xnb. But if i want to add another model (fbx or x) , then the contentbuilder will delete some of the generated xnb file in the destination dir ( i don't know why , and neither can i solve it ). It confuses me a lot when i'm ready to make a editor for XNA in the WinForm. The sample of the WinFormContentLoading Sample can't help , because it only generate ONE temporary .xnb file , while i want mutiple models to be loaded ( not load once , may be twice, first time 10 models and then 20 models from file ). I've no idea how to solve the problem, any idea is really appreciated!!! THANKS A LOT!!!!!

There is no built in way to load Models directly from FBX or X at runtime. You can implement your own reader (or find one online) of those files and build your own structure of VertexBuffers and IndexBuffers and use those.