window reflections in high rise

[Tim Portlock]

I have a lot of experience modeling in Maya but not so much on shading/rendering side. I am working on a series of images that will include contemporary high-rise buildings with highly reflective windows. I am particularly interested in how the reflections are distorted by each window. I have attached reference images that I will be working from which should give you a sense of what I am talking about. In my source images, you can see how each individual window warps the reflection in a unique way. I am wondering if anyone can point me to information for how to approach this? As far as I can figure, there are two basic ways to do this. 1) find a shader that will warp the reflection differently for each pane of glass on the buildings. 2) do a render pass just for the windows and composite in a sky image. For the first approach, this seems like it may be very processor intensive and put a lot of extra geometry (i.e. extra work) into the scene to create the reflected image. For the second option, I am not sure how I would get the comped reflection to warp differently for each individual windowpane. I am expecting to use Arnold for this but can go with something else if you it makes sense.

[Lewis Garrison]

I work in Max no Maya, but I'm sure the same ideas apply. I achieve this effect by putting a noise map in the bump slot set to a very low intensity. Then for closeups I make sure the windows are one object and do a UV unwrap. This will make the mapping have a slight offset from window to window.

[Tim Portlock]

Thanks Lewis. That is a clever idea and sounds fairly straight forward to execute. I will give that a try.

[Stephen Thomas]

On a curved building with faceted (i.e. straight) glazing sections you should be able to achieve this effect quite easily, since each panel is at a slightly different angle. Just make sure to clear your smoothing groups.