Getting fast renders in Cinema 4D is more than checking Render Instances or keeping Global Illumination Settings low. Sure you also need to tame your Anti-Aliasing and blurry reflection settings. Rendering is always a compromise of speed versus quality.
Simple solutions are:
- Shadow Maps over Area Shadows
- Managing Global Illumination Settings
- Managing Anti-Alias Settings in the Standard Renderer
- Are Blurry Reflections necessary
- Are the Ray Depth and Reflection Depths set too high for the scene?
- Get a new fast computer :(
Using a 3rd Party Solution like Greyscalegorillas HDRI Studio Pack can speed overall time up by using some render presets, and helps eliminate the need to experiment with different render settings but that plugin cost extra money. What about some solutions you might not have considered or might have forgotten about?
Render Bucket size - Default vs. Custom
By default, Render Bucket Size is set to Automatic. Maxon recommends you keep it that way, but what fun would it be not to find some ways to hack the system and speed up your renders? This is truly a case by case basis depending on the scene and your computer, but I’ve tweaked my render bucket settings to see a speed up in renders by 5%. I've heard other people say they've gotten a 25% increase. Swing the settings too far in either direction and the renderer won’t efficiently use your systems resources. There will be scenes you will try this on and it will have not impact in render time at all.
Note: You can only change the Render Bucket size in the Standard Renderer.
Standard Renderer Results When Varying Render Bucket Size
- Automatic: 7:45
- 35x35: 7:41
- 20x20: 7:40
- 80x80: 8:10
- 128x128: 8:50
Side Note, results for this scene using the Standard Renderer are terrible compared to the results you get using the Physical Renderer. Keep reading below!
Physical Render Settings
When to use the Physical Renderer vs. Standard Renderer. Many factors can impact this decision. Basically the way I look at it is the simpler the scene, the more you will probalby using the Standard Renderer. The Reflectance Channel in Cinema 4D works the best and is faster using the Physical Renderer. If you want realistic metal surfaces in Cinema 4D, there is just no way around it.
Fixed. Adaptive. Progressive. Sampling Subdivision. These are all options that pop up in the Physical Render settings box. And lets not forget about the Custom setting. You could spend a lot of time with that trying to get the perfect result.
- Use Adaptive for your renders.
- If you are going to add grain to your final render in compositing, then don't worry about a little grain in the 3D render.
Look at the difference between the two renders below AND the difference in their render times when it comes to choosing what renderer to use. Insane, right?
Do yourself a favor and save a lot of time by changing the Sampling Quality to AUTOMATIC when using the Physical Renderer. A bunch of options get greyed out but thats okay, we want to simplify things. Let Cinema 4D figure things out for you while you spend the extra time iterating.
By default the Shading Error Threshold is set to twenty percent (20%), which is a little noisy but fine for test renders. Drop the Shading Threshold down to five (5%) for the final render. That's all you have to change to get a really nice looking render... if you've taken the steps to light it properly of course.
Looking for that perfectly clean render and don't care about render time? Go ahead and change the Shading Error Threshold to one to three percent (1 to 3%). With the renderer set to Automatic and 1%, you get the same result as Adaptive set to High Settings.
If you are noticing that shadows or blurry reflections are a bit noiser than other parts of the scene, that is where you can adjust Blurriness Subdivision and Shadow Subdivision while not needlessly increasing render time on other aspects of the scene by lowering the Shading Error Threshold needlessly. This is apparent in the above 5% examples.
Below are examples of using the Physical Renderer with Global Illumination with and without Radiosity Maps. Notice how these render times are significantly fasterer than using the Standard Renderer on the same scene used in the Render Bucket size examples.
TIP // Radiosity Maps will really speed up your GI renders! Read HERE
Reflectance Channel - Beckmann vs. GGX
The Reflectance Channel is great. It aids in creating physically accurate materials to those found in 3rd party rendering solutions. It also has a lot of settings to mess around and get lost in. It you don’t know what you are doing you can really slow up your renders without seeing any difference in quality. This channel can make or break you in getting a render completed on time.
For example, lets look at the difference between using Beckmann vs. GGX. Below are sample renders with the same material but with different reflection types. Notice how they look very similar but the render times vary greatly. These are pure renders with no roughness calculated.
Beckmann is the fastest option to render, however GGX is best for metal surfaces, so ultimately it's up for you to decide how physically accurate you need your material to be and if the render time is worth it. I'm guessing that if you are doing a lot of fast motion graphics, you can get away with Beckmann.
We all know it's about what settings you use when it comes time to render in Cinema 4D. Setting the tolerance of one setting too high can mean the difference between hours of render time when really that setting is not making a render any different than a much more modest setting.