hi, i´ve been getting this strange artifacts and i don´t know how to correct them:
rendering with MentalRay a simple scene with only 2 shaders: 1 basic lambert (with dirtmap on the diffuse) and 1 basic blinn ( i also tried phong).
maya render (production quality)
MentalRay (samples: 1-3 Box 1.0 1.0)
MetalRay (samples: 1-3 Lanczos 4.0 4.0)
If it ever hapened to you or if you know what it is… please help me :).