DOI: 10.13140/RG.2.2.20000.28167 https://www.researchgate.net/publication/324993603_BLENDER_CYCLES_-_Glass_Material_BSDF_Reducing_Noise_-_Tutorial

1. BLENDER CYCLES – Glass Material BSDF +
Reducing Noise - TUTORIAL
Assoc. Prof. Dr. Eng. Tihomir Dovramadjiev
Technical University of Varna
MTF, Department Industrial Design
tihomir.dovramadjiev@tu-varna.bg
DOI: 10.13140/RG.2.2.20000.28167
https://www.researchgate.net/publication/324993603_BLENDER_CYCLES_-
_Glass_Material_BSDF_Reducing_Noise_-_Tutorial

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Blender software – download
& license
Blender.org: “Open Source 3D creation.
Free to use for any purpose, forever.”
Blender software download:
https://www.blender.org/download/
Blender software license:
Free to use Blender for any purpose, including commercially or for
education. This freedom is being defined by Blender’s GNU General
Public License (GPL).
https://www.blender.org/about/

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Blender Cycles Renderer »
Materials » Surfaces
Surfaces:
● The surface shader defines the light interaction
at the surface of the mesh. One or more
BSDF’s specify if incoming light is reflected
back, refracted into the mesh, or absorbed.
Emission defines how light is emitted from the
surface, allowing any surface to become a light
source.

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Blender Cycles Renderer »
Materials » Surfaces
●
Terminology:
● BSDF
Stands for Bidirectional Scattering Distribution Function. It
defines how light is reflected and refracted at a surface.
● Reflection
BSDFs reflect an incoming ray on the same side of the
surface.
● Transmission
BSDFs transmit an incoming ray through the surface,
leaving on the other side.
● Refraction
BSDFs are a type of Transmission, transmitting an incoming
ray and changing its direction as it exits on the other side of
the surface.

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Blender Cycles Renderer »
Materials » Surfaces
BSDF Parameters
A major difference from non-physically-based renderers is that direct light
reflection from lamps and indirect light reflection of other surfaces are not
decoupled, but rather handled using a single BSDF. This limits the
possibilities a bit, but we believe overall it is helpful in creating consistent-
looking renders with fewer parameters to tune.
● Roughness
For the glossy BSDFs, the roughness parameter controls the sharpness of
the reflection, from 0.0 (perfectly sharp) to 1.0 (very soft). Compared to
hardness or exponent parameters, it has the advantage of being in the
range 0.0 to 1.0, and as a result gives more linear control and is more
easily textureable. The relation is roughly: roughness = 1 - 1/hardness

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Blender Cycles
Fig. 1. Blender Cycles Render / default interface.

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Blender World
Fig. 2. Blender World. Surface > Color > Black. RGB: 0,0,0.

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Blender Cycles Render: Test
Fig. 3. Blender Cycles Render: Test.

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Adding Plane to Scene
Fig. 4. Adding plane to scene. Add > Mesh > Plane.

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Resizing Plane
Fig. 5. Manual resizing plane with “s” key.

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Transform: Cube Location
Fig. 6. Transform: Cube Location (View > Front (Numpad 1) + View
Persp/Ortho (Numpad 5)).

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Blender Cycles Render: Test
Fig. 7. Blender Cycles Render: Test.

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Light Options
Fig. 8. Light Options.

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Blender Cycles Render: Test
Fig. 9. Blender Cycles Render: Test.

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Adding Glass Material
Fig. 10. Adding glass material (Type of active data o display and edit:
Material).

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Adding Glass Material
Fig. 11. Adding glass material. Surface > Use Nodes > Surface > Glass
BSDF / Beckman.

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Blender Cycles Render: Test
Fig. 12. Blender Cycles Render: Test. Image has noise.

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Reducing Noise
When performing a final render, it is important
to reduce noise as much as possible. Here we
will discuss a number of tricks that, while
breaking the laws of physics, are particularly
important when rendering animations within a
reasonable time. Click to enlarge the example
images to see the noise differences well.
https://docs.blender.org/manual/en/dev/render/
cycles/optimizations/reducing_noise.html

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Path Tracing
Cycles uses path tracing with next event estimation, which is not good at rendering all types of
light effects, like caustics, but has the advantage of being able to render more detailed and
larger scenes compared to some other rendering algorithms. This is because we do not need
to store, for example, a photon map in memory, and because we can keep rays relatively
coherent to use an on-demand image cache, compared to e.g. bidirectional path tracing.
We do the inverse of what reality does, tracing light rays from the camera into the scene and
onto lights, rather than from the light sources into the scene and then into the camera. This has
the advantage that we do not waste light rays that will not end up in the camera, but also
means that it is difficult to find some light paths that may contribute a lot. Light rays will be sent
either according to the surface BRDF, or in the direction of known light sources (lamps,
emitting meshes with Sample as Lamp).

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Blender Cycles – Reducing
Noise – Samples & Clamp
Indirect
Fig. 13. Reducing Noise. Sampling > Samples: 400; Clamp Indirect 3.50.

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Add Modifier – Solidify
Fig. 14. Adding Modifier / Solidify to Cube.

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Add Modifier – Solidify
Fig. 15. Solidify Modifier. Thickness: 0.2 and Apply.

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Final Result - 1
Fig. 16. Blender Cycles - Render. Final result - 1.

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Adding Glass Sphere to
Scene
Fig. 17. Adding glass sphere to scene + yellow / orange color.

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Final Result - 2
Fig. 18. Blender Cycles - Render. Final result - 2.

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Resources
Blender software
https://www.blender.org/
Cycles Renderer » Materials » Surfaces
https://docs.blender.org/manual/en/dev/render/cycles/materials/surface.
html#surfaces
Glass BSDF
https://docs.blender.org/manual/en/dev/render/cycles/nodes/types/shad
ers/glass.html
Reducing Noise (Path Tracing - CC-BY-SA 4.0)
https://docs.blender.org/manual/en/dev/render/cycles/optimizations/redu
cing_noise.html
How To Reduce Noise In Cycles Render [duplicate]
https://blender.stackexchange.com/questions/18304/how-to-reduce-
noise-in-cycles-render?
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