Materials with alpha casts weird "interlaced"shadows on a ground plane

[kirk2345]

It's ok on a screen but in final  output picture ("include alpha" on) the shadows turns into some weird interlaced  appearance with the same horizontal 1pix strokes in normal , depth and "clown" passes.

https://www.dropbox.com/s/mwdzc8jraa98ttc/interlaced%20shadow.jpg?dl=0

Beside the passes itself ignore alpha in the materials completely.  It's   very disappointing and makes them pretty useless.   I hoped to do some orto renders of tree models and looks like Keyshot can't do proper foliage  at all in the passes.     

win8.1-64   Keyshot6 Pro  , Zbrush bridge ,    To reproduce the problem just put some texture with alpha on something .

[Allan]

I have the same problem in Keyshot 6. The same scene in Keyshot 5 doesn't have the problem.
If I save my rendering as a png, tiff or psd with an alpha channel, then the jagged edges occur.
I have discovered, that the problem goes away, if I use a coloured or dark background instead of a white. But that does not give me the transparent shadows I need.

[Niko Planke]

This is probably caused by the aliasing.
Did you try using max samples/time rendering mode instead.
That should remove the jagged edge contour.