Corona 15 noise and denoiser settings: noise level limit, UHD Cache and AI denoising

This guide covers Corona 15 for 3ds Max (27 May 2026). The settings are in the same locations and have the same names in Corona 14. Corona handles noise differently from V-Ray: it uses progressive rendering and keeps adding passes until you stop it or it reaches a limit. So noise management comes down to two decisions: When should you stop the render, and which denoiser should you use to clean up the remaining noise?

1. Render limits: passes, time or noise level

Menu path: Render Setup › Scene › General Settings › Rendering limits

There are three limits:

• Pass limit: The render stops when it reaches the specified number of passes.

• Time limit: A duration limit set in hours, minutes and seconds.

• Noise level limit: The render stops when it reaches the target noise level, expressed as a percentage.

If more than one limit is enabled, the render stops when it reaches whichever limit comes first. For example, if you set 100 passes and 1 minute, whichever limit is reached first applies. Set a limit to 0 to disable it. If all limits are set to 0, the render continues until you stop it.

For the most predictable workflow, use Noise level limit, because it keeps image quality consistent. Heavier scenes take longer, but output quality remains consistent from project to project. A time limit, on the other hand, is useful for drafts along the lines of “whatever we can get in 10 minutes” before a client meeting.

2. Choosing the right noise level limit

According to Chaos’s official documentation:

• Noise level limit works only when adaptivity is enabled. Adaptivity is enabled by default and, according to Chaos, should never be turned off.

• A higher value means the render finishes sooner with more noise; a lower value means it takes longer and finishes cleaner.

• For final renders, 2–3% is generally considered acceptable.

• Noise is measured every X passes. X is the Adaptivity recalculation value in Development / Experimental Stuff; its default value of 5 does not need to be changed.

If you’re using a denoiser, start with a value slightly above 2–3% and compare the result at 100% zoom. Increase it gradually (for example, 3 → 4 → 5) and watch for fine details such as wood grain, fabric and wall textures starting to look “painted.” Set the limit one step below that point.

3. Denoising mode: five options for five different uses

Menu path: Render Setup › Scene › General Settings › Denoising

There’s also Gather data for later, which only collects denoising data. Use it when you want to denoise the image later.

The Denoise amount parameter controls the blend between the noisy original and the denoised image. Its most useful feature is that you can adjust it interactively in Corona VFB after rendering. In other words, you can say “denoise it a little less” without rendering twice.

4. The hidden pitfall: the High Quality image filter

The Chaos Help Center explicitly notes a limitation: the High Quality filter type under Render Setup › System › Frame Buffer › Image filter cannot be used for technical reasons with AI denoising (NVIDIA or Intel) or AI upscaling. If an AI denoiser isn’t working as expected because of settings carried over from an old template scene, this is the first place to check.

5. Performance tab: usually, leave it alone

Menu path: Render Setup › Performance

Chaos’s Performance tab documentation says most of these settings work best at their defaults. Here’s what to know before changing them:

Increasing Light samples multiplier to 8 because an interior render “isn’t cleaning up” is a common intervention that usually doesn’t help. The issue is often with the scene itself: light entering through a narrow window, very bright small reflections, or an unnecessarily high Max sample intensity.

6. Production Upscaling: save time with a lower resolution

Introduced with Corona 12 Update 1, this AI-based production upscaling feature renders the image at half width and half height (one-quarter of the pixels), then enlarges it to the final resolution using the NVIDIA AI Upscaler. According to Chaos, that means about 4× faster rendering. The underlying SDK is hardware-independent and also supports AMD and Intel GPUs.

There are two caveats. First, as noted above, it can’t be used with the High Quality image filter. Second, as Chaos’s product manager has pointed out, flickering can occur between frames. So use caution with animations featuring moving cameras. For still images and quick client drafts, however, it can be a very effective shortcut.

Recommended workflow

1. Lighting setup: Interactive rendering + NVIDIA GPU AI denoising, if available. A noise-free preview with lower detail helps you make lighting decisions faster.

2. Draft: Time limit (for example, 5–10 minutes) + Intel CPU/GPU AI.

3. Final render: Noise level limit (2–3%, or slightly higher with a denoiser) + Corona High Quality or Intel AI. Adjust Denoise amount while viewing the result in the VFB.

4. Animation: Use the Animation (flicker-free) preset with UHD Cache; don’t use NVIDIA GPU AI.

Before / after: What changes?

Switching from the habit of “Pass limit 0, Time limit 0, Denoising None, and stop the render by eye” to this setup gives you:

• Consistency: With Noise level limit, all 12 cameras in the same project finish at the same quality level. You avoid having one remain noisy while another renders pointlessly for 40 minutes.

• Render time: Relaxing the noise limit when using a denoiser cuts out the slow cleanup phase in the final passes. As noise decreases, each new pass makes a smaller visible difference, and that’s also the most expensive part.

• Flexibility: Since you can adjust Denoise amount after rendering, feedback like “it’s over-denoised and looks plastic” doesn’t require a rerender.