This set include 6 tree models with parametric snow material.The material allows control of direction and amount of snow cover. These two parameters are animatable.
No matter of tree rotation, snow cover will be on the right side of mesh. Have a look at video that I provided.Even instance copies with different transforms works correctly.
Tree meshes are rather optimised: the scene with 6 trees meshes is 1 300 000 faces.As material setup include specific 3ds Max maps, I did include only 3ds Max file 2017, 2020.Both Vray and Corona scenes included. Vray GPU may need additional tweaking, as maps may work differently.I put instruction file explaining how to easily control snow cover. No advanced skills is needed.