Parti Volume shader

Getting Mental Ray shaders to work in 3ds Max can be pretty frustrating. This is a scene to test out the Lume Parti Volume shader on a large urban model. The sun is a Photometric targeted spot set at 15000 lx at 4000 m. To fill in the dark area's and bring out the ambient occlusion of the material there is a skylight with its multplier at 0,3. The Parti Volume shader is attached to the camera shaders volume slot of the renderer tab of the Render Setup screen and then instanced to the Material Editor. Get it? The trick here is to fidlle with the Step length settings and the Scatter color. Mininum (spelling error here in max??) Step Length = 0,1m and Maximum step Length is at 0,5m. The scatter color is very dark yellow (a brighter color washes out the scene to much at the horizon). The exposure control is mr Photographic with the physical scale set to Unitless at 8000.
The difficulty with the Lume Beam shader and the Parti Volume shader is to get the ratio of the photographic exposure settings and the brightness of the lights right. Try setting your scene up with simple geometry and fast materials whilst playing with these settings.