Radiosity Normal Mapping?

[Raildex]

How would someone achieve radiosity normal mapping?
According to some Half Life 2 Papers, we need to generate three lightmaps, one with a different directional component. How would that be achieved?

[ds445]

I haven't tried it explicitly with lightmapper, but I assume if you manually set the normals of the geometry to be facing each the three directions you want to use for your directional light maps (Valve calls this the radiosity normal basis, if I remember the paper correctly, and I assume most implementations would want them in the local coordinate system of the polygon, i.e. expressed in the TBN basis) and bake those three resulting lightmaps, that's what you would get :)