Ray Tracing

Ray tracing is one of the most powerful 3D imaging techniques for rendering photorealistic pictures. It allows the creation of very sophisticated images and can require the adjustment of many parameters. The major drawback of this technique is long render times. It’s the usual tradeoff: quality or speed.

The optical principle behind ray tracing is that light follows exactly the same path, whether it travels forwards, or backwards. So, what ray-tracing does, is follow all those light rays reaching the camera back through the scene, up to the light source. For each and every pixel of a picture, the render engine will trace the ray of light back into the scene, decide what objects were hit by the ray, bounce that ray back if the surface is reflective, transmit it through the object’s surface if it is transparent, and eventually head for light sources, making sure nothing is getting in the way, that would shadow the object. A simple scene made out of a water plane and a ground plane requires tracing 7 rays per pixel! (And this is if you are not using any elaborate features, like soft shadows, blurred reflections or transparencies, depth of field, super-sampling etc.).

This complexity is the reason why ray tracing yields such beautiful results, and also why it is so slow. However, numerous optimizations and special ways of displaying pictures as they render have enabled Vue rendering to produce much faster pictures.

Ideally, Ray tracing is recommended for interior views.

Path tracing

The Path Tracer, a hybrid CPU / GPU renderer, is physically unbiased render mode that naturally simulates many effects that have to be specifically set with other methods, such as soft shadows, depth of field, caustics, and indirect lighting. GPU acceleration allows for interactive rendering updates while editing your scene. The Path Tracer doesn’t need additional computation for features like various soft effects (for example, soft shadows, blurry reflections and refractions, and depth of field), nor any kind of pre-pass calculations for indirect lighting. The only artifact that can be generated by the Path Tracer is high-frequency noise.

Path tracer supports powerful AI denoisers like the CPU-based Denoiser by Intel, and the GPU-based denoiser from NVIDIA to remove high-frequency noise. NVIDIA's GPU based denoiser requires a Maxwell based card or later such as Pascal or latest generation Turning based card. Amazing renders can be produced with fewer samples per pixels. In order to use one of the denoisers you must set the following new Configuration variable:

Variable	Value	Description
MS_PATHTRACE_DEFAULT_DENOISER	None	Denoising is disabled
	NVIDIA	NVIDIA Denoiser is enabled (will require supporting hardware)
	INTEL	Intel Denoiser is enabled

If the variable is unset, it will use the Intel Denoiser. If left blank or if any value other than Intel or Nvidia is added, then there will be no denoising.

Note: Once the denoiser is enabled, any path traced renders in the VUE render history will be denoised by the denoiser you have chosen, Intel or NVIDIA. If you don't like the result of NVIDIA's denoiser for example, you can try switching to Intel and all your history images will be seen denoised with it.

Interior scene rendered without denoising

Interior scene rendered with NVIDIA denoiser enabled

Interior scene rendered with Intel denoiser enabled

Many Vue rendering features are not supported with path tracing.