I’m currently rendering a scene in Corona Renderer 12.2 and I’m experiencing what feels like unusually long render times, and I’d love some feedback on whether this is expected or if there are optimizations I should be considering.
Here are my system specs:
GPU: NVIDIA RTX 4080 Super (I know Corona is CPU-based, but just listing it for context)
CPU: AMD Ryzen 9 7950X
RAM: 128 GB DDR5
Renderer: Corona Renderer (latest version)
Scene complexity: ~20 million polygons
Render resolution: Square ratio of 4880 × 4880
Render settings:
Noise level limit: 5%
Pass limit: 100 passes
UHD Cache enabled (default settings)
The issue is that each image is taking 4–5 hours to render. I’m unsure if this is normal for a setup like mine, or if something in my scene or render settings might be causing inefficiency.
Is this render time typical for this resolution and scene complexity? Are there any suggestions for optimizing performance without sacrificing too much quality?
What is the scene you are trying to render? Is it an enclosed environment with many lights and cuastics? If so, then that would be why. If it is an exterior with a car sitting on a road, then that is way too long.
Its an interior scene, I wouldn’t necessarily say it has lots of lights and caustics there around 12 lights in the scene and few objects with glass material applied.
I have 7950x and I don’t remember doing any render on it for over an hour. I would say the scene is not optimized (or setup) well. Maybe there is a small part in it which causes the noise level to stay high. But 4-5 hours on a 7950x is too much, even for high resolutions.
Hi, we cannot help you without knowing what exactly you are rendering. That’s because both the expected render time and advice on how to optimize a scene are highly scene-dependent. The best thing you can do, especially if you are not comfortable with sharing your scene publicly, is contacting our support team here: https://support.chaos.com/hc/en-us/requests/new
First, exterior windows were made simple (thin, no refraction).
There were very far away objects (maybe empty, e.g. “Books 006_002-mesh169”) which were simply deleted - I don’t think they were used in the scene.
Now main part: the library was lit with lights which had hard time getting out of the “covering” and reaching different parts of the scene. Specifically the round chandeliers - light sources were placed inside refractive glass (better make them simple, too). The floor lamp had similar setup.
Rayswitch was used to make the GI slot of these objects into a simpler materials to be calculated.
This was mostly it.
You can further improve the render times (less noise in given time) by decreasing the Max Sample intensity. Even a value of 6 would give fine results, specifically in the library part.
Pop on over to the Corona Academy and watch Chapter 14 Creating the Chandelier. It has an extensive look at what happens when placing a light source inside a glass material as this can have a dramatic effect on render times, and the various ways you can speed things up using the Rayswitch etc. as was done in this situation to speed things up. Chaos is the linky.
