Hi there,
I’ve just started learning blender recently and I was wondering how could I improve this render, I’m using Cycles with default settings, 128 samples and ‘OptiX denoiser’
Here’s the current result
Glow more
Which one looks better?
What are the effects of camera distance and focal length (now 30mm) on render quality?
Thank you
Well, for a final render, you should use open image denoise rather than Optix. Optix is faster, but usually has a lower quality, it’s more intended for viewport previews.
Those settings have no effect on quality, because quality is per-pixel of the render and those settings don’t change the resolution of the render or the number of rays used on each pixel.
What will affect the quality of your render is the sampling settings (noise treshold, min/max samples).
The max samples is easy to understand, if you reach that number of samples, the render is finished.
The min samples represents how many samples will be completed before the noise treshold starts being used. If you leave it at 0, Blender will pick a value for you, based on the number of max samples.
The noise treshold (also known as adaptive sampling) represents the amount of noise that’s allowed to exist in a pixel. When a pixel falls below that amount of noise, it stops receiving samples, so the render doesn’t waste time on parts of the image that are already clean. If every pixel is done, the render will end before the max samples are reached, which should in theory mean that the noise is perfectly even across the image if that happens.
In your case, I think you need to pick a number yourself for min samples (try 128 to start with and see if it can be lowered or if it needs more). Some of the highlights seem to have gaps in their noise pattern, which means that the noise treshold kicked in too soon and couldn’t fully find the reflections, so it wrongly assumed some pixels were over, simply because the reflection hadn’t even appeared yet. This is a common problem with the noise treshold: it can miss parts of complex reflections if the min samples are too low.
I have a different set of glare settings to propose.
Change the quality from “medium” to “high”. The medium setting applies the effect to a lower resolution version of your image. This allows the effect to spread farther, but can cause jagged edges.
The effect will have become smaller, so set the “size” to 9. It will now have a bit more spread than before, but with a higher quality.
Reduce the “mix” number to make the glare more subtle and so it doesn’t blend into the actual glowing shape and hide it. The exact number will depend on the level of emission in the material.
Thank you for such a detailed answer, it does help to understand the whole process clearly, unfortunately I cannot set min samples or I couldn’t find the setting, probably that’s related and limited to CPU rendering as it’s super old, only NLM and OptiX available, I do plan to upgrade GPU in the near future, to achieve the full potential of Blender.
This is what I’ve got with these settings, both sized at 9:
Mix -0.5
I see, your problem isn’t cpu vs gpu, it’s that you are using an old version of Blender. In that case, you should upgrade if you can, the newer versions have access to “open image denoise”, which is a much better denoiser than what you have right now, so you would benefit even without a good GPU.
If you are in a version of Blender that has adaptive sampling, the settings I talked about do exist, but they have different names and UI.
I personally do like the glow, especially the one that’s a bit reduced in strength (glow like that can look a bit over the top if you overdo it), but it all depends on what you are trying to do and the scene’s intentions.
