Splitting Up Verticies

Hi, (sorry if this is an unnecessary post)
I posted about a weird shading thing that happened when I was using Tidy Tile Mapper and Directional Light (also with all types of light.) Jessy said that;

Your cubes are only 8 vertices. You can’t do proper lighting with that, because the faces share normals. You’re going to need to split up the faces so that each one has its own set of four normals/vertices.
http://docs.unity3d.com/Documentation/ScriptReference/ModelImporter-normalSmoothingAngle.html

weirdshading.jpg

So my question is, how would I split up the faces to do this? In blender - I tried subdividing but I still had the same problem.
And isn’t this also a waste of resources? Instead of 6 faces being rendered 24 faces have to be rendered. Can someone explain why this is because I’m quite confused.

Thanks,

Yharooer

Jessy meant that each vertex on each face needs to be separate to make the sides of the cube appear flat.

This is because the normal of the vertex needs to be different for each face. You will still only render 12 triangles but there will be 24 vertices rather than 8.

Each vertex can only have 1 normal - so if you make a box out of 8 vertices then the normals can’t be pointing differently for each face because there would only be 8 normals and you need each corner of each face to be pointing in the same direction to get flat shading.

10241-ybtff.jpg

There is normally a setting in the modelling package to suggest how the face should be treated and exported (or perhaps smoothed).