3.5Cats_AndHalfAFish

It seems there are a couple of ways to import Blender objects into Unity ...

• You can manually export your Blender object as .fbx (Autodesk), .dae (Collada), .3ds (3D Studio), or .obj (Wavefront). You then need to copy this file into the Unity Assets folder.
• Or, and this is the easiest way, you just save your blend-file (as is) into the Unity Assets folder.

I have found that it is much easier to split larger blend-files into smaller ones (create separate files for most of the objects in your scene).

The official documentation states that :

'Unity natively imports Blender files. This works under the hood by using the Blender FBX exporter, which was added to Blender in version 2.45. Unity currently imports : all nodes (position, rotation, scale, pivot points, & names), meshes (with vertices, polygons, triangles, UVs, & normals), bones, skinned meshes, & animations.'

Just remember : you need Blender 2.60 or later !!! (In some earlier versions the FBX export is broken.)
Also : textures & diffuse color are not assigned automatically !!! You need to manually assign them by dragging the texture onto the mesh in the Scene View in Unity.

Q : Why am I only seeing half of my imported object ???
I made sure to set the normals to 'double sided' in Blender ... But still : I can only see 1 side ???

A : The answer can be found here :

• You can either create a 2-sided mesh in Blender (double the number of vertices !).
• OR : You can use a 2-sided shader in Unity.
  Some of the Unity shaders are 2-sided ; some are not. Eg/ the particle shaders ("Particles/Alpha Blended") are 2-sided ; the diffuse shader is not.

If you want a 2-sided version of one of the built-in shaders which isn't currently 2-sided, you need to :

• download the built-in Shader Source file
• duplicate the required shader into your Assets folder
• set (or change) the culling value to "Off"
• use your new custom shader with your material