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Luxrender GPL Physically Based Renderer

SLG Rendering Type

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The Rendering Types refer to the different rendering engines that SLG contains. They define the way you images are being rendered. Currently four options are available.

Choosing the right rendering engine is one of the most important settings in SLG. Notice that there is no best Rendering type, you always have to look on your hardware, on the render scene and what you want to render. In one case SPPM is the best, in other cases Path or Direct.

On this section and the following sites we will discuss what features the different Rendering Types offer. And also what does not work in a Render mode because a few things are displayed that don't work in the chosen render mode.

For a quick overview take a look at the SLG Rendering Types comparison Table.



General SLG settings

Here you find a brief description of the Settings that are available in each Render mode.

  • Full path to SmallLuxGPU's executable
  • Full path where the scene is exported
  • Scene Name
  • PLY
  • UVs
  • VCs
  • VNs
  • InfiniteLight BF
  • Camera Motion Blur
  • Accelerator Type
  • Film Filter Type
  • Tone Mapping
  • Image File Format
  • Low Latency
  • Batch Mode
  • Wait
  • Telnet
  • Echo
  • Periodic save interval
  • Native Threads
  • OpenCl Threads
  • CPU
  • GPU
  • GPU Workgroupsize
  • Platform
  • Devs

render type descriptions


Path Tracing that only uses GPU can be very fast when the scene is small enough. The big advantage is that the scene data gets transferred to the GPU one time and then the GPU can work with its VRAM. The GPU has a very high bandwidth and a very low access-time to the VRAM. Try to make sure that the render scene is not bigger than the VRAM.

  • No participating meta supported

PathGpu RenderPanel


Direct is old-school ray tracing: the rendered image account only for incoming direct light (i.e. no global illumination, no caustics, etc.).


SPPM (Stochastic progressive photon mapping)

SPPM is an evolution of classic photon mapping where few problems of the original algorithm were addressed. For instance, there is no need to store photons in a map (so the quality of the result doesn't depend any more on the amount of memory available). It is unbiased, etc. SPPM has the noticeable characteristic to render some extremely hard to render light path like Specular->Diffuse->Specular reflections.

SPPM is good for complex lighting scenarios with glass and caustics. On the other hand, shadows turn to out better with other render engine settings.


Path (path tracing)

Here Rays are randomly shot from the light source and when they hit something they get reflected, broken or absorbed. When you start Rendering not many paths are calculated and the picture looks noisy. But with more and more rays it becomes cleaner and cleaner.