Mixing Raytrace and Rasters

I need help on a movie project where on some large shots I have a little city visible and many many foliages…
I can build the light correctly and display the foliages without raytrace the fps is limit, but ok.

But on raytraced mode as soon as I display the foliage I get like 0.2 fps :wink: And I can’t render any frames without crashing

I absolutely need to combine raytraced (for buildings) and Shadow mapped (for many many foliages).

How can I mix the two? I can’t find a way