November 25, 2021 Rosie Dinh

A comprehensive guide on basic render settings on Redshift

Redshift is a powerful GPU-accelerated renderer, built to meet the specific demands of contemporary high-end production rendering. In other words, Redshift is tailored to support creative individuals and studios of every size. In fact, Redshift offers a suite of powerful features and integrates with industry-standard CG applications. Over the past few years, more and more designers are using Redshift for rendering and dramatically speeding up their render times thanks to this renderer.

For today’s article, let’s explore the overall basic render settings on Redshift, so that users could have a full understanding from the root of this render to put a firm basis for more advanced render setting in the future.

Basic render settings on Redshift

As we all know, Redshift features two modes for approaching its render settings, a streamlined Basic mode and a more detailed Advanced mode. Basic mode consists of a small selection of frequently used render settings while Advanced mode exposes all of the available render settings. If you’re just getting started with Redshift or prefer to keep things simple the Basic mode is a great way to adjust your render quality without the need to fine tune render parameters.

Bucket Quality

First comes the Bucket Quality setting. This is one of the most important steps in render settings on Redshift. It allows you to quickly adjust overall render quality by switching between preset sampling Threshold values. Higher quality modes decrease the Threshold value which improves render quality and reduces noise but at the cost of render time. The Custom preset is automatically switched to when you enter your own custom threshold value. Basic mode uses Automatic Sampling by default, if you want manual control over your sample counts you must switch to Advanced mode to disable automatic sampling.


The Threshold parameter refers to Unified Sampling’s Adaptive Error Threshold and is controlled by the Bucket Quality presets or by the user when set to Custom Bucket Quality. Lower Threshold values improves render quality and reduces noise but at the cost of render time. 

Bucket Quality Threshold
Low 0.100
Medium 0.010
High 0.005
Very High 0.001
Custom User controlled


The Denoising checkbox allows you to quickly toggle denoising on and off. Denoising allows you to easily render images at a reduced baseline quality (lower sample counts) and increased speed at the expense of some potential accuracy. Denoising can only do so much and a balance must be struck between Bucket Quality and the denoiser engine of choice in order to find what works best for your project. 

Denoising Engine

Redshift has three built-in Denoising Engines and they can easily be switched between here, each one with their own general pros and cons.

  • OptiX – Very fast and can be used during interactive rendering but can have more trouble cleaning noise compared to alternatives. 
  • Altust Single – Slower (renders the frame once before denoising) and non-interactive but produces good results for final quality renders. 
  • Altus Dual – Slowest (renders the frame twice before denoising) and non-interactive but produces great results for final quality renders.

The images below were rendered with Bucket Quality Low in order to better demonstrate the differences of the different Denoising Engines due to the low sample count resulting in more visual noise with Bucket Quality: Low

Motion Blur

The Motion Blur checkbox lets you quickly toggle Motion Blur on and off. If a Motion Vector AOV is enabled in your scene all Redshift motion blur will automatically be disabled in the beauty render as this would be undesirable for a Motion Vector AOV.

Motion Blur Steps

This controls the number of linear motion blur steps that Redshift will use to represent the trajectory of cameras, lights and objects. More steps means the trajectories will be more accurate but also more memory will be used.

Deformation Blur

This checkbox toggles Deformation Blur for Motion Blur on and off. Deformation Blur tracks the motion of individual vertices and can be memory-intensive, if your objects do not have animated deformation this parameter can be left disabled for increased performance. In the example images below notice how the trajectory of the moving lantern is more appropriately rendered as the Motion Blur Steps are increased. All renders were taken from the same animation, the only thing changed was the Motion Blur Step count.

Global Illumination

The Global Illumination checkbox lets you quickly toggle bounced indirect lighting on and off. For the most realistic lighting Global Illumination should be left enabled but it will increase render times. By default Basic mode uses a combination of Brute Force for primary bounces and Irradiance Point Cloud for secondary bounces. In the example images below notice how the bounce lighting from the floor and wall next to the lantern is realistically filled in when Global Illumination is enabled.

Combined Depth

The Combined Depth, and the associated depth parameters covered below, control how many times a ray of its respective type can bounce or pass through an object until it is terminated. The higher the depth value the more realistic the rendering result at the expense of render times. It specifies the maximum limit for global illumination, reflections, and refraction combined. This means that if the individual depth value for global illumination, reflections or refractions is higher than the Combined Depth the resulting render will still be capped at the Combined Depth value. Increasing Depth values can quickly and greatly increase render times in scenes with many bounces. In general it is a best practice to use as few as you need to achieve the result that you desire.

Global Illumination Depth

The Global Illumination Depth parameter puts an individual cap on how many times an indirect lighting ray can bounce. Interior scenes where many indirect bounces are required for realistic lighting make this a good parameter to increase.

Reflection Depth

This parameter puts an individual cap on how many times a reflection ray can bounce.

Refraction Depth

The Refraction Depth parameter puts an individual cap on how many times a refraction ray can bounce or pass through objects.

Transparency Depth

The Transparency Depth parameter puts an individual cap on how many times a transparency ray can pass straight through objects. Transparency is utilized for things like Opacity in the Redshift Material to go much deeper than complex refractions and render much faster than Refractions.Transparency Depth is not limited by the Combined Depth parameter.

The test scene was modified specifically to demonstrate the impact of the depth settings by putting 8 panes of glass in a row in front of the camera. Each pane of glass has actual thickness meaning that in order for a ray to fully pass through one requires at least 2 rays, since there are 8 panes of glass a minimum of 16 rays is required to see through all 8 panes. You can see below that the glass on the lantern is not even visible until the refraction trace depth is high enough to get through all 8 panes of glass and then the lantern glass itself. These same limitations are imposed on each ray type by their individual caps as demonstrated in the last example where the Global Illumination and Reflection Depths are reduced well below the Combined Depth resulting in the loss of most of the reflections and the global illumination. 

Hardware Ray-Tracing

When enabled this will utilize any available hardware accelerated ray-tracing as long as you are rendering with compatible video cards like the Nvidia RTX series graphics cards.The impact of hardware accelerated ray-tracing varies from scene to scene, with scenes that spend more of their time specifically on ray-tracing generally seeing more of an improvement with hardware RT enabled. Non-ray-traced effects like irradiance point cloud and irradiance cache GI are not accelerated by hardware RT.


Hope that after this article, you can understand almost all basic render settings on Redshift and can take advantage of it to create wonderful projects in the future. 

One interesting thing for you! iRender is a Professional GPU-Acceleration Cloud Rendering Service provider high performance machines for rendering tasks, CGI, VFX with over 20.000 customers and being appreciated in many global rankings ( e.g: CGDirector, Lumion Official, Radarrender, InspirationTuts CAD, All3DP, VFXRendering). We are proud that we are one of the few render farms that support all software and all versions. Users will remotely connect to our server, install their software only one time and easily do any intensive tasks like using their local computers. Redshift users can easily choose their machine configuration from recommended system requirements to high-end options, which suit all your project demands and will speed up your rendering process many times.

High-end hardware configuration

  • Offering the most powerful graphic card currently, RTX 3090. The servers range from Single and Multi-GPU servers: 1/2/4/6/8 x RTX 3090 with 24 GB vRAM capacity, fitting to the heaviest images and scenes. NVLink/SLI requested for bigger vRAM.
  • A RAM capacity of 128/256 GB.
  • Storage (NVMe SSD): 512GB/1TB.
  • Intel Xeon W-2245 or AMD Ryzen Threadripper Pro 3955WX CPU with a high clock speed of 3.90GHz.
  • Additionally, iRender provides NVLink (Request) which will help you increase the amount of VRAM to 48GB. This is a technology co-developed by Nvidia and IBM with the aim of expanding the data bandwidth between the GPU and CPU 5 to 12 times faster than the PCI Express interface. These servers are sure to satisfy Blender artists/ studios with very complex and large scenes.

Let’s see rendering tests with Redshift on multi-GPU at iRender:

If you have any questions, please do not hesitate to reach us at any time. Register an ACCOUNT today and get FREE COUPON to experience our service. We are availabe 24/7 to support you!

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Thank you & Happy Rendering!

Source:Redshift documentation

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Rosie Dinh

Hi everyone. Being a Customer Support of iRender, I always hope to share and learn new things with 3D artists, data scientists from all over the world.


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