Light rendering above the geometry but its placed behind it

[Gabiru]

Greetings, im working on a animation where i have small dot lights scattered on my background (left side). Im having a problem where the dots looks like rendered above the geometry which causes flickering when i use blur combined with zdepth, we can see the majority of the dot blurred but we still watching part of it as it is. Any fix to this?
Here are 2 images, one is raw render other is camera blur applied on zdepth pass.

[maru]

Hi, sorry, but it is hard to understand what we are dealing with without knowing how the scene is made. Would it be possible for you to contact us at https://support.chaos.com/hc/en-us/requests/new and upload some additional content such as the scene itself, or at least images explaining what exactly you are doing?

Thank you in advance!

[Gabiru]

hey Maru, thanks for your reply.
Here is a frame of my scene. So the blue dots over the reddish background are small light spheres. The idea is to create some bokeh effect on After Effects with them, we tried to do it directly on Corona Cam but it renders really slow.
Unfortunately as the previous post shows there are some pixels where the light looks like above the geometry surface but it's actually being scattered on the background. Then when I apply zdepth element it creates flickering. Let me try to show you, theres a detailed screenshot where I zoomed the yellow circle zone to show you what's happenin and also the same frame blurred on After Effects. As you can see Zdepth cant get the job done because theres some bleeding into the geometry.
Hope you can help with this

[romullus]

This is happening because of antialiasing. Objects' edge pixels are partially transparent because 3D geometry does not perfectly align with screen pixels, that's why you need antialiasing, because otherwise all the edges would look horribly jagged. As useful antialiasing is, sometimes it can cause issues, like in your case. That's why usually you want certain passes to be aliased. You can try to turn image filtering off in render setup system tab and render z-depth for 1 pass. That should effectively disable antialiasing.

As alternative, you could try to achieve everything in 3D. Corona since recently has gotten new DOF highlight solver, which should help you to render bokeh highlights with significantly less noise in reasonable time. You can find this option in render setup performance tab.

[Gabiru]

thanks for your answer @romullus very detailed information.
I guess whatever way i render the zdepth it will not solve the problem because the light is already bleeding in the beauty element. I need to somehow solve the beauty element maybe playingwith highlight clamping values?
i tried DOF corona solver but to remove the noise it would tike like 15min each frame, without DOF i can render each frame for like 35sec lol