odd SSAO 'erasure' when object moves in front of the effect

[darbotron]

Hi

I purchased your SSAO solution yesterday, it looks great in the test scene

There does however seem to be a slight issue with it, in that the SSAO contribution from objects closer to the camera seems to overwrite that of objects further away.

Here's 3 snips of screenshots which show what I mean, in these screenshots, the object is moved parallel to the camera plane from left to right so that it occludes the ssao darkened area in the corner of the room.

This shows the ssao in the corner of the room before the object moves in front

before overlap, corner fully darkened by ssao

00.png (146.57 KiB) Viewed 8500 times

First noticeable "anti artefact" - ssao darkening on wall to right of corner (in the magenta box) is 'erased' (or at least significantly lightened) as the object is approaches a point where it will occlude the ssao darkened area

ssao darkening on the wall to the right of the corner is 'erased' as the abject approaches

01.png (143.93 KiB) Viewed 8500 times

Second "anti artefact" - ssao darkening in the corner visible immediately above the object is 'erased'

ssao darkening above the object is 'erased'

02.png (142.62 KiB) Viewed 8500 times

The distance at which this 'erasure' effect as shown in the second image starts to occur seem to be directly proportional to the 'Radius' parameter on the inspector UI, and it looks to be as if the SSAO calculations from the object closer to the camera (but not close enough to anything to cause SSAO darkening) might be overwriting the SSAO darkening in the corner behind it.

This might be deliberate but it appears to me to be incorrect & might easily have escaped your notice, especially as there is nothing moving about in the demo scene

Alex

[Ricardo Teixeira]

Hi

I purchased your SSAO solution yesterday, it looks great in the test scene

There does however seem to be a slight issue with it, in that the SSAO contribution from objects closer to the camera seems to overwrite that of objects further away.

Here's 3 snips of screenshots which show what I mean, in these screenshots, the object is moved parallel to the camera plane from left to right so that it occludes the ssao darkened area in the corner of the room.

This shows the ssao in the corner of the room before the object moves in front

00.png

First noticeable "anti artefact" - ssao darkening on wall to right of corner (in the magenta box) is 'erased' (or at least significantly lightened) as the object is approaches a point where it will occlude the ssao darkened area

01.png

Second "anti artefact" - ssao darkening in the corner visible immediately above the object is 'erased'

02.png

The distance at which this 'erasure' effect as shown in the second image starts to occur seem to be directly proportional to the 'Radius' parameter on the inspector UI, and it looks to be as if the SSAO calculations from the object closer to the camera (but not close enough to anything to cause SSAO darkening) might be overwriting the SSAO darkening in the corner behind it.

This might be deliberate but it appears to me to be incorrect & might easily have escaped your notice, especially as there is nothing moving about in the demo scene

Alex

Greetings,

Sorry for the delayed reply, we have a few Forum issues that we still need to ironout. For direct support, feel free to contact us via [email protected]

Unfortunately, you've stumbled upon one of the common SSAO limitations. Although the effect is extremely fast, it does have a few issue such as occluded artifacts or even incorrect AO on the edge of your screen. You assumption is correct, the larger the radius, the more noticeable the issue will be.

Apologies for the inconvenience.

Thanks!

[darbotron]

No Thanks for getting back to me

It's not really a deal breaker, but it might be worth listing it as a known issue / limitation of the shader - especially if there's no plan to fix it

Cheers,

Alex

[Ricardo Teixeira]

No Thanks for getting back to me
It's not really a deal breaker, but it might be worth listing it as a known issue / limitation of the shader - especially if there's no plan to fix it
Cheers,
Alex

Hello,

Awesome, happy to know that it's not a deal breaker. Unfortunately, it's a limitation of the actual technique, also present in similar solutions. Screen-space effects are awesome but there's always an expected compromise.

We actually plan to replace the technique used with something more modern and efficient soon.

Stay tuned!