Light sources and objects in ARCHICAD Library

From ARCHICAD 18 the Lightworks rendering engine has been replaced to Cinema 4D rendering engine. The parametrisation of the LIGHT command has been changed according to the new rendering engine. This post introduces the structure of the Light sources and objects in the ARCHICAD Library working with the new rendering engine.

In the ARCHICAD Library there are four basic light sources:

  • Omni Light: simulates uniform rays shining out from a single infinitely small point in space in all directions
  • Spot Light: simulates light radiating from a single infinitely small point in space and has a cone of influence in a specific direction.
  • Area Light: simulates a realistic soft lighting distribution from a definable two- or three-dimensional body
  • Infinite Light: simulates coherent and parallel infinite light rays

The Light objects in the General Light Sources folder use all the functions provided by the Cinema 4D engine (except a few parameters with fixed values). The parameters can be edited on a hierarchic User Interface. These objects use the basic light sources according to the following table:

Light Source Light Object in ARCHICAD Library
Omni Light General Light, IES Light with undefined *.ies file
Spot Light Spot Light
Area Light Area Light, Window Light
Infinite Light Sun Object, Parallel Light

Light Objects in ARCHICAD Library

TipsAndTricks_LightsInLib_Ex_omniLight

General Light

  • 2D, 3D Geometry: fix center point, light source is rotatable in case of “Illuminate One Direction Only”
    is set
  • Light Source: Omni Light
  • Effects on the example:
    • Visible Light: On, Type: Volumetric
    • Reduce Density over Distance: On
    • Reduction Starts: 1200mm, Ends: 3000mm
    • Noisy Visible Light: On
    • Noise Type: Noise

 
 

TipsAndTricks_LightsInLib_Ex_spotLight

 
Spot Light

  • 2D, 3D Geometry: center point and target point can be set
  • Light Source: Spot Light
  • Effects on the example:
    • Fade Out Gradually: On
    • Visible Light: On, Type: Volumetric
    • Reduce Density over Distance: On
    • Reduction Starts: 0mm, Ends: 3000mm
    • Reduce Density towards Edges: On

 
 

TipsAndTricks_LightsInLib_Ex_areaLight

Area Light

  • 2D, 3D Geometry: center point and target point can be set
  • Light Source: Area Light
  • Settings and Effects on the example:
    • Area Shape: Sphere
    • Shape is Visible In Render: On
    • Shape is Visible In Reflection: On
    • Noise Illumination: On, Type: Hard Turbulence
    • Surface Caustics: On
    • Lens Flare Glow: On
    • Lens Flare Type: Star 1

 
 

TipsAndTricks_LightsInLib_Ex_windowLight

Window Light

  • 2D, 3D Geometry: can be fit to window plane, rotatable (for example can be adjusted to skylight)
  • Light Source: Area Light
  • Effect on the example:
    • Illuminate One Direction Only: On

 
 
 
 

TipsAndTricks_LightsInLib_Ex_sunLight
 
Sun Object

  • 2D, 3D Geometry: center point can be set, fix target point
  • Light Source: Infinite Light
  • No effects on the example

 
 
 
 

TipsAndTricks_LightsInLib_Ex_parallelLight

 
Parallel Light

  • Differs from Sun Object only in editing options
  • 2D, 3D Geometry: fix center point, target point can be set
  • Light Source: Infinite Light
  • Effects on the example:
    • Reflexes: On, Type: Wide Angle
    • Ignore Specular Channel: On
    • Illuminate One Direction Only: On

 
 
 

TipsAndTricks_LightsInLib_Ex_IESLight

 
IES Light

  • 2D, 3D Geometry: fix center point, rotatable light source
  • Light Source: IES Light, if there is no *.ies file loaded in the Library, then Omni Light
  • Effects on the example:
    • Surface Caustics: On
    • Falloff – Reduce Energy over Distance: On

 

Interior, Street Lamps

The Lamps in the ARCHICAD Library could be divided into three groups by the used light sources:

  • Omni light source (Desk Lamps, Street Lamps)
  • Spot light source (Wall Lamps, Ceiling Spot Lamps)
  • Area light source (Floor Lamps)

These Lamps use the light sources defined in the lightMacro_m, where most of the rendering engine functions have given a fix value (for example: Lens Flare, Noise, Caustics, Visible Light etc…). Only basic light functions are available for the user in these objects:

  • Absolute Light Intensity (Light Distance or Light Intensity)
  • Shadow Quality
  • Representation of the light cone in 2D and 3D

Changes and parametrisation of the GDL light command

The internal engine is still available, this part has not been modified at the LIGHT command compared to ARCHICAD 17:

light	gs_color_red,
	gs_color_green,
	gs_color_blue,				! RGB

	! parameters for internal rendering engine
	shadow,					! Shadow on/off
	radius,					! Light Cone Radius
	alpha,					! Angle 1   /maximum light/
	beta,					! Angle 2   /angle falloff light/
	angle_falloff,				! Angle Falloff
	distance1,				! Light Start
	distance2,				! Light Stop
	distance_falloff,			! Distance Falloff

In the following section the additional parameters for the Cinema 4D rendering engine can be given:

! parameters for Cinema4D rendering engine
	ADDITIONAL_DATA	c4d_gen_Type	= c4dGenType,
	c4d_gen_Color			= c4dGenColorBuiltIn,
	....................		= ....................,
	....................		= ....................,
	....................		= ....................,
	....................		= ....................,
	....................		= ....................

In the ADDITIONAL_DATA section of the LIGHT command Cinema 4D engine parameter values can be set. If a parameter’s value is not set, the script will run with the default value of the engine. The available Cinema 4D engine parameters have a specific nomenclature, the overview of these parameters (list of parameters, types, defaults, minimum and maximum values) is in the Cinema 4D Documentation.