Rendering white outlines/fringe on PNG shadow only

I’m rendering PNG images on a transparent background with shadows only option.

  • Transparent background is necessary for web editing.
  • Shadow also for contrat and sitting products on a context.
    I try to understand and get rid of the white fringe that appears around the solids, especially on the ground shadow.
    Rhino creates a white fringe/contour which are pale pixels.
    It’s like if Rhino fail to interpret the shadows around parts sitting on a non existing ground and background.

This is an issue with the shadows-only groundplane. It is a known issue ( RH-84042 Ground Plane - Shadows only, grainy edges in render . Not visible to public since confidential material is referencde). I have added this topic to the issue.