We sometimes have unwanted ‘contact shadows’ where ‘pointy objects’ meet the floor. For example in this shot at the bases of the legs of most of the furniture. We have tried everything we can think of, but the only way to get rid of these artifacts is to move the camera closer. The shadow seems to be always away from the camera (the position of the sun/hdri doesn’t seem to influence it).
Is anyone else experiencing this? Is there anything that can be done to fix this?
This appears to be by design. Some sort of SSAO with decay.
@Demian_Gutberlet is this a known feature/bug/just get used to it thing?
@Clemens_Musterle do you perhaps have any insights?
i usually solve this problem by moving those objects(chairs, tables) SLIGHTLY about 2~5MM above.
Thanks for the tip. We tried moving it up but the issue remains. We’d need to move it so much that you’d immediately see they are floating.
@Clemens_Musterle @Demian_Gutberlet
Is this on your radar? Are we doing something wrong?
@Pieter_2 , thank you for the patience, I really do appreciate it.
Allow me to detail what our developers add to this. What we have here does indeed look like a known behavior (unwanted) of screen space based ambient occlusion (SSAO). To get more technical, when just using the depth value of the image, the algorithm can not tell if there is an actual corner (where AO should correctly be applied) or one object occluding another (where it should not).
So, unfortunately, it is unwanted behavior, but also kind of unavoidable at the moment. This may still be something we can improve upon (most likely through ray/pathtracing) in the future but there is no ETA for that yet.
I am aware that this answer may not be entirely satisfying, but that is the current status I wanted to share. If any questions come up about this topic, let me know as always. 
Thank you Demian!
Thank you for the explanation, it does help knowing that you guys are aware but that there’s no immediate solution. It’s unfortunate, but I understand that with real time visualization (or any visualization really) some trade offs have to be made, and that’s a process of continuous improvements.
Presumably the SSAO is baked into the rendering and cannot be turned off through the UI, right?
I’m afraid not - Especially not unless lowering the Rendering Quality substantially is an option.
It has to be added that SSAO for the most part does improve the image, usually by a fair margin despite such artifacts, but I do also understand the want to turn it off entirely due to that.
All I can do is forward your request to PM but I have to say that it is not likely we’ll add such an option soon since it usually does not pose so many problems as to make it worth turning off entirely.
Still, it is noted and I do appreciate your understanding and feedback Pieter.
I understand. If the image would look worse overall, I think turning SSAO off would not really be a solution.
@Pieter_2 …I had a thought for you on this. Often when I have issues related to shadows I find a zoomed in closeup sometimes clears it up. You can them manually comp in the closeup detail rendering into the overall.
Thanks for the tip. We ended up fixing this in post as you suggested, but it’s a very time consuming job when you have many renderings being updated often.
Ideally we would be provided with some automated means of dealing with artifacts created by overly aggressive optimization, especially for rendering high resolution still images. This is the primary reason I recently inquired about a tiled rendering feature (RE: Tiled High Resolution (16K + ) Renderings) as I believe this would address the concern we are discussing. A user selectable “tile size” would seem to be a flexible way of overcoming these types of artifacts for high resolution rendering.
