QUESTION:

I am having some problems with surface insolation calculation. As far as I know, ECOTECT gives one figure per surface, and so I used subdivision-tiling tool in the modify menu. But the end result seems not valid, as all the newly divided surfaces have 0 value even if it's facing north. What mistakes am I making here?

ANSWER:

You need to ensure that with the surface sub-division you either specify an offset distance or delete the original surface. Otherwise, ECOTECT believes that the surfaces are shading each other as they occur exactly on top of each other.

In addition, you need to ensure that the surface normals are pointing in the right direction -- i.e. towards the sky and not into the object. You can check this under Display » Surface Normals then select and reverse those that are miss-aligned under Modify » Reverse Normals.