Cinema 4D / BodyPaint 3D Program Documentation Reference Cinema 4D Cinema 4D Visualize, Broadcast, Studio
Function available in CINEMA 4D Visualize, Broadcast, Studio

ProRender

General

Tip:
Note that in the following cases, shaders must be compiled for the graphics card that are then saved to your user directory:

  • Render with a new version of Cinema 4D
  • Render with a new graphics card
  • After a graphics card or OpenCL driver have been updated
  • Activate motion blur and modifications to the render settings
  • Activate Subsurface Scattering, using different noises and shaders

Other than in Cinema 4D R19, this is not done for all shaders at once but as necessary, which speeds up the render workflow considerably.

This can take a while - during which Cinema 4D may appear to be frozen. All you have to do is have a little patience.

Tip 2.
For Windows systems: If you are not using an OpenCL 1.2-capable graphics card (e.g., graphics processors built on mainboards or very old graphics cards), Opencl drivers for the CPU have to be installed. Otherwise you will receive an error message in Cinema 4D.

OpenCL drivers for CPUs can be found here:

  • Intel processors: https://software.intel.com/en-us/articles/opencl-drivers#latest_CPU_runtime
  • AMD processors: http://support.amd.com/en-us/kb-articles/Pages/OpenCL2-Driver.aspx

ProRender is a special physically correct renderer that runs on the graphics card (multiple graphics cards on a single machine can be used simultaneously). Since graphics cards are specialized for rendering, they often render much faster than most CPUs. If your graphics card is not compatible, ProRender can also run on the CPU - but slower (this is, however, still in experimental mode!).

ProRender can be selected in the Render Settings menu. If selected you can render to the Picture Viewer or in the Viewport via IRR.

ProRender can also be used as an interactive preview renderer (can be activated in the view’s ProRender menu).

Here are the advantages and disadvantages of a GPU renderer in short:

Advantages

Disadvantages

Noise and render times

Compared to older Cinema 4D renderers, rendering will not be done in sequence bucket for bucket in the Viewport or Picture Viewer but as a complete image with the noise dissolving as the rendering progresses:

Render progression from left to right.

ProRender shoots numerous samples for each pixel into the scene. The result (= color) of each sample is continually taken into consideration for each pixel and added to the previous samples in the Picture Viewer and subsequently averaged. As the rendering progresses, more samples will be generated per pixel: the result constantly improves.

The fundamental difference between ProRender and older renderers lies in the theoretical "infinite" nature of this process. The render result constantly improves over time. The image’s grainy/noisy look will steadily be reduced until the noise has been removed entirely after an infinite amount of time.

Of course nobody had time to render indefinitely - and this is also not necessary. The render process can be aborted at any time, either manually (if you think the image looks good enough) or by definition (e.g., after a defined amount of time).

The human eye is accustomed to interpreting a certain amount of high-frequency noise in an image as looking realistic. The sensor in a digital camera also produces such noise. As such, noise is much less irritating than a lower-frequency noise (= larger, sometimes flickering regions), which can, for example, be produced when rendering with Irradiance Cache.

Note that it is possible, within certain limitations, to smooth noise using external software (e.g., Photoshop), which can also reduce image detail (the initial noise should not be too extreme). However, there is no real substitute for actual render time.

Physically correct rendering and Cinema 4D settings

ProRender does not support all Cinema 4D settings. Since it’s specialized on physically correct rendering, many settings and workflows that do not support this approach cannot be used.

For example, if you take a look at the various light settings: In reality there are no lights with a linear brightness falloff or hard shadows, or radial color falloff, etc. Also, several cameral functions (e.g., stereo rendering, lens distortion, etc.) as well as material functions (channels such as Diffuse, Environment, Fog, Glow and Luminance, etc.) won’t work. Multi-Passes and several objects (e.g., Floor, Background, Environment, etc.) will also not work, and the Compositing tag is only partially supported.

As you can see, the limitations primarily affect elements that are important for rendering such as lights, cameras and materials.

Tip:
When ProRender is selected, all settings for materials, lights, cameras, tags and render settings that do not work with ProRender will be grayed out. Non-realistic settings such as negative light intensity can be defined but will have not effect.

Note also the Limitations.

On the other hand you don’t have to worry about numerous settings. For example:

Generally speaking, you should concentrate more on creating realistic-looking renders with ProRender and not worry about using effects or "tricks" to get the look you want. Note the following:

ProRender and light sources

Light sources are a very important element for renderers. Area lights (e.g., PBR Light) should be used for the highest level of realism. You can also use Omni, Spot or Infinite lights but these cast less realistic shadows (hard raytrace shadows) and real-world lights all have a volume or a surface.

For rendering, ProRender does not differentiate between an Area light and an object that has a luminous material.

GI solutions when rendered using the Standard Renderer did not offer an equal sample depth for both light sources, which is no longer the case. With a sample depth of 1, for example, only surfaces that can be "seen" directly will be illuminated.

RELEASE 20

ProRender and the Physical Sky

ProRender works with the Physical Sky but not all functions are supported. Similar to shaders that are not natively supported by the graphics card, ProRender bakes a 2D sky internally (with the omission of all light sources, which the Physical Sky would otherwise use). The size of the baked texture can be defined in the Physical Sky’s Details tab (Texture Preview Size).

All Physical Sky effects that can’t be baked cannot be rendered by ProRender. In turn, the settings that apply to ProRender can be found in the following tabs:

  • Time and Location
  • Sky
  • Clouds
  • Details

Non-applicable settings will be grayed out.

Miscellaneous

RELEASE 20

Cinema 4D R20 supports display color shaders and the MoGraph Color shader

Other things you should know about light:

ProRender and material

The most important change regarding materials is the removal of the specular function. ProRender "only" offers reflections via the Reflectance channel (note in conjunction with this the New PBR Material command). You should therefore use Area or polygon lights if you want light to reflect directly on an object.

Miscellaneous

Optimal scenes

A GPU renderer is a non-directional, unbiased path tracer. These types of renderers are best suited for the following scene types:

Scenes that are well-lit, with numerous regions that are illuminated directly are ideal. Noise will be reduced quickly in these images. Interior space scenes that are illuminated with a few small lights are more difficult to render correctly.

This doesn’t mean that scenes won’t be rendered well after a longer render time, but it will take longer for the noise to be eliminated.

Unbiased basically means that a physically correct render result can be achieved if the render time is long enough. On the other hand there are the other two older renderers, the Standard and Physical Renderers, which are biased renderers. These renderers often work with simplified tricks, e.g., to minimize render times and memory use. These renderers don’t always achieve physically correct results. However, experienced artists can still achieve excellent, convincing results.

Artefacts on low-res objects

If such artefacting occurs in reflections and refractions (in this example on a low-res cylinder), increase the subdivision. The same issues - with the same solution - can occur where directly lit regions neighbor shadowed regions.

Limitations

The following list does not necessarily include all points (individual elements that are not supported are grayed out or not available if ProRender is activated in the Render Settings).