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« on: 2025-08-29, 23:19:25 »
No-one is calling you an idiot, nor did anyone say "you are a fool yourself". There was no such wording anywhere - that said, sorry you feel that the tone of replies implied that or gave that impression.
It does remain true though that from what I see here (not having tried the scene myself), there is no actual bug here. It will always be possible to come up with material settings and scene parameters that can consume memory or slow rendering massively, and that sounds like what has happened in this case.
Those are definitely extreme values. Max Ray Depth of 100 would be suited for, for example, a scene with a mirror reflecting a mirror 100 times before losing reflection, and as the tooltip says, it is usually best left at the default. There are very very few situations where a Max Ray Depth of more than 25 will make any visual difference, less where that difference would be necessary.
On IOR, "The highest IORs are found in metamaterials like the one created in 2011 with a positive IOR of 38.6, and in natural materials, the highest known IOR belongs to Germanium at approximately 4.05 in the infrared range and diamond at 2.42 in the visible spectrum. " - so again, a high IOR like that is not physically realistic. Now, bear in mind Corona used to not be as physically realistic as it is today - over time, we've continued to refine its realism, and that means some set ups that used to work, or even used to be necessary, no longer work, or are no longer required.
The maximum IOR in the Corona Physical Material is now 3.0. While the Legacy material is not going anywhere, some of the extreme values it allows may not work so well any more. So a scene that uses old set ups may have problems running under a new version of Corona, not because something is broken, but simply because things have changed (become more realistic, have been optimized, have new algorithms to calculate them, etc.) We do try and maintain backward compatibility as much as possible, but it's not always fully possible.
You mention that the scene is fine from some angles, and this makes sense based on what has been described - at certain angles, rays will spawn back and forth between two materials, where those materials are set to not obey proper energy conservation (so the rays don't reduce in importance and can be ignored, but instead all the rays have to be calculated, requiring more and more memory) where at the same time the scene settings have been changed to also allow that "almost infinite continued propagation" of rays, rather than clamping them after 25 bounces. At some angles, rays will bounce off one object, miss the other, and there is no problem. At some angles, rays will bounce off object 1 to object 2 to object 1 to object 2.... and so on, with settings that don't prevent this excessive spawning of more and more rays.
This does mean that the fix is in the scene, not in Corona - realistic values that follow physical laws are best to be used. This is kind of like the ray equivalent of setting displacement to World with units of .00001 - while it is in theory possible to calculate, it will run out of RAM trying to do so, and this is not a bug as the fix would be similar, adjust the values being used in the scene.
Old scenes no longer rendering, no longer looking the same, or even crashing now when they didn't before, is not always something broken in Corona. As mentioned, we do try and maintain backward compatibility, but it is always a possibility that something - especially where the settings are quite extreme - now causes slow rendering or a crash where it didn't before.
So no gaslighting here, there really isn't anything broken in Corona, and no-one is calling you an "idiot" or similar as it isn't your fault either, you set up a scene that worked fine back then, so both sides of your definition are incorrect. All it comes down to is that the solution here is that the scene and material settings need to be updated to account for the updated version of Corona, and neither you nor Corona are "broken".
Hope this helps!
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