Lightmapping problem, squares appearing on imported model.

Can someone please explain why this is happening when I bake my scene?
The model has been exported from 3DS Max '13 to FBX format.

If you experience this problem ensure that your UVW Map is correct otherwise it will cause these anomalies in the lightmapping process.

To do this in 3DS Max:

  1. convert mesh to poly.
  2. select the modifier tab on the right
  3. select the ‘UVW Unwrap’ modifier
  4. select the entire mesh
  5. click open ‘UV Editor’
  6. select > convert edge to face
  7. mapping > flatten mapping.

then Export. This should give your polygons UVW real-estate to map texture/light to.