I am following the steps of this tutorial to simulate IES luminaire:
However on Step 5, after loading the IES in the scene (I can see my IES geometry displaying) my DIVA materials menu is still the same, I am not able to assign the luminaire material to the polygon.
Do I need to use another materials menu or should my materials menu change as soon as I load the IES? I hope you can help.
That page is pretty much just for DIVA-2.0. If you are using the Materials > Load IES File command in DIVA-3.0, you don't need to go through that process. Basically, in DIVA-3.0 the workflow would be as in this link. Which is a small tutorial I produced for my class at some point. All you have to do is keep the automatically-generated geometry on the layer it is imported to using DIVA-3.0.
Brilliant thanks :)