Ok, so I have Hammer v3.5, and the lastest fgd file, however when I place something like a func_resource, or a hive object, the model doesn't display. It works fine for other games, like Hostile Intent, but for NS it doesnt work, any ideas?

You have to setup your MOD directory and game directory correctly

Also make sure you aren't too far away, you can change the render distance in options.

models are available in 3.5 Beta, not 3.5

It is not simple that you just have a lastest fgd file without editing and then the model display in Camara. It's wrong. So you need to edit your fgd. How do you edit it? I'm so sorry. I don't know about it as I haven't made NS map before. But i know hot to edit the cs fgd and make the cs model display in 3Dview. And I think that the method of editing cs fgd should be simular to NS. (I'm not sure completely)

1. Make sure that you have already fill in all the blanks in "Game Configuration". I would like to show my setting as below.
2. Copy your NS fgd as backup
3. Go to "Game Configuration" and select the fgd in "Game Data Files" then click "Edit"
4. Now it would appear a notepad. In CS, if i want to make all the models appear in 3Dview. I need to change two codes. For example, I want to make the Terrorist appear in 3Dview. I would change the code from "@PointClass iconsprite("sprites/CS/Terrorist.spr") base(PlayerClass) = info_player_deathmatch : "Terrorist start" []" to "@PointClass studio("models/Terror.mdl") = info_player_deathmatch []" (In that code, "info_player_deathmatch" is a entity that locate the start point of Terrorist and "models/Terror.mdl" locate the Terrorist model.)
5. Them open a map you may see that the Terrorist and other Models would display in 3Dview.

I'm really very very sorry about that I can't teach you in NS case but i think that the method of editing fgd should be same as CS. The main point of editing just need to change the code of player start point. If you don't know what i am talking about or make you comfused, post in this thread and i will try to help.

If you have any question you should ask for help. KEEP WORKING and KEEP STUDYING

The fgd included with NS 3.0 already supports the feature, no need to edit. It's a problem of configuring the directories.