Dan Lee

Hmm, that is curious.
Yes, please do file a bug along with your scene file.
Thank you!

Hi. Upcoming daily build (21.0.693) addresses this issue where karma had trouble picking out best instance when it's close to camera.
Note that parts of the nearest instance mesh that are offscreen may be diced at lower rate (depending on offscreen quality) and it may show on other instances that are in full view of the camera. For that, you could either increase offscreen quality (under Rendering->Geometry and Shading->Dicing tab), or increase Dicing Minimum Depth via Render Geometry Settings LOP to enforce minimum level of tessellation, or use a static dicing camera.

zzhj
Hi, is there a way to tell karma to set distance as deep value when deep camera map is enabled? Because in arnold or some other renderer, distance is the deep value when rendering via a fisheye camera, which is similar to Cylindrical Camera in some way, in karma or mantra deep is always equal to z depth.

Thanks for any help.

You can enable "DCM use Hit Distance" toggle (under Deep Output tab) to use hit distance for z/zback values instead of projection depth.