AO affects shadows on a matte material..

I have a object composited over some footage with a transparent plane underneath that receives shadows.

If I do a basic render the shadow is nice and strong, no problems.

But I have noticed that if I turn on AO and render then the shadow on the transparent plane either fades out or disappears altogether.

Is there any way around this?

Thanks in advance,

Tupik :slight_smile:

AO simulates totally ambient lighting where there is no light coming from any specific direction, so it makes sense that it would “fight” shadows. AO is a dirt shader that darkens creases to kinda simulate shadows (actually more like a lack of radiosity and spec from angled light into corners) - but not shadows. You should either bake AO, or make two render passes - one with shadow and the other with AO, and then composite them however you want to get the effect you want.Another option would be to use AO "Sub"tract.

Fantastic. Thank you so much for clearing that up for me.