Render issues with trees at distance & size

[dfcorona]

Hi,

I've ran across this issue a few times. I tried to solve it myself but cannot find a solution. I'm pretty sure this is a bug because this behavior doesn't happen in V-Ray. Attached you can see two renders. One at 1080p and the other at 4k.  You can see how the trees in 4k are much lighter than the same trees rendered at 1080p. Also, you can see the major issue that the trees get much darker with distance. If I go into IPR mode, as I zoom into the background trees, they get much lighter the closer I get. I tried this in V-Ray, this doesn't happen and the trees look the same no matter the distance or the size of the render. How do I solve this issue or is this a bug?

Max 2025.3
Corona 13, hotfix 1

[pokoy]

I recently ran into this with a grass patch model.
Make sure to disable map filtering for the diffuse bitmap. It's likely caused by a black background in that map where pixels get filtered to a darker tone progressively with increasing distance. It's best to disable filtering on all maps used on fine details anyway as it can be too aggressive.

[dfcorona]

I recently ran into this with a grass patch model.
Make sure to disable map filtering for the diffuse bitmap. It's likely caused by a black background in that map where pixels get filtered to a darker tone progressively with increasing distance. It's best to disable filtering on all maps used on fine details anyway as it can be too aggressive.

Your right! Nice find. I could of sworn I tried the filtering. I'm surprised that this is default for Corona since it creates such an issue.  I wonder if turning off the filtering will create issues with animation?

[maru]

So it was this ancient issue: https://support.chaos.com/hc/en-us/articles/4528578885649
I wonder why it doesn't happen in V-Ray by default. We can try to find out.

[dfcorona]

Hi Maru,

Yes this is a pretty major issue that many users probably don't even realize is happening in there scenes. Somehow this doesn't happen in V-Ray, But by default this should not be happening in Corona.

[maru]

In my simple test the issue seems to be the same in Corona and V-Ray. If anyone has a V-Ray scene where this is clearly not happening, please contact us at https://support.chaos.com/hc/en-us/requests/new