Hi ! Thank you for your help ! Face orientation, scale, displacement only, subd, cycles are ok... And I add a question : how to keep the sparkles? Because Denoise removes this tiny little dots reflecting the light.... Here is some quick render at 24 samples, with different parameters... Thanks
Thank you Omar, Dwayne and Adrian !
Yes ! Snow Shader works best with Color ramp set to Bspline, Noise set to 3D and Cycles with 256 samples ! Thanks for your help !