FirstStage import assets via Unity, so the guides below explain how to get Unity set up to export into FirstStage.
There after, where the assets come from is up to you, and generally there are both export to Unity guides from the tool developer, as well as import inot Unity from Unity themselves. Here is a list of tools and guides.
NB - Some guides may go out of date due to Unity and tool developer software updates.
Tool > Unity Import Guides
General general guides:
|3d modelling tool||Export to Unity (.fbx) from tool guide||Import to Unity (.fbx) from tool guide|
|SketchUp||Exporting FBX files||Importing Objects From SketchUp|
|Blender||Export FBX||Importing Objects From Blender|
|3ds Max||Exporting from 3ds Max to an FBX File||Importing Objects From 3d Studio Max|
|Maya||Exporting from Maya to an FBX file||Importing Objects From Maya|
|Cinema 4D||FBX Export||Importing Objects From Cinema 4D|
|Cheetah3D||Importing objects from Cheetah3D||Importing Objects From Cheetah3D|
|Modo||Game Asset Exporter||Importing Objects From Modo|
|Lightwave||Export Group / FBX||Importing Objects From Lightwave|
|Reallusion Character Creator 3||Character Creator 3 Tutorial – Exporting CC3 Base Characters to Unity Exporting FBX Characters (New for v3.1)|
|Human Generator for Blender||Human Generator for Blender - REVIEW (video)|