Table of Contents:
In general, settings under this section of the YafaRay UI are used to give specific YafaRay properties to light sources and cameras in the Blender 3D scene. Only a limited number of Blender settings are taken into account by YafaRay. The general workflow is:
With this feature, objects in the scene can act as area light sources. The soft shadows produced by area lights need to be sampled several times and then interpolated to reduce noise. This type of light takes more time to render in contrast with point light types such as spot and point.
First of all, you must select the mesh you want it to act as a light source. Then you must click on the Objects main button. Finally you must activate the Enable Meshlight button. To change the light color, just click on the rectangle next to Meshlight color to open a Color Picker.
Example of Meshlights, rendered with Bidirectional.
Other area light types:
Lights settings are mostly controlled by the YafaRay UI. In Blender, the only actions required are placing lights and choosing a Blender light type. Arealight size and spot beam parameters are controlled in Blender panels though. In YafaRay, lighting power is controlled by a couple of settings (Color and Power) available in the python UI for every light type, therefore the Blender Distance and Energy buttons don't have any effect at all on YafaRay.
Once a light is placed and its type defined in Blender, select it and press Object/Light/Camera main button. The python UI will automatically change to show specific settings for the type of light selected. It you want to change a light to another type, you have to change it in Blender first.
When you create or select a Lamp light in the Blender 3DWindows, the python UI will let you choose between two options to do this kind of job, Point and Sphere. A Point light is a typical omni directional point light source as in Blender Internal with hard shadows, while a Sphere light is a spherical area light source which can produce soft shadows.
The Sphere light settings are:
|Comparison between point light (left) and spherelight (right). Notice the different shadows.|
Other area light types:
When you create or select a Sun light in the Blender 3DWindows, the YafaRay UI will let you choose between two kind of lights to do this kind of job, Directional and Sun. Directional light is a traditional sun light model which produces parallel rays and hard-edged shadows.
The new YafaRay Sun light is a more advanced concept and will help us to get blurred-edged shadows when the shadow itself gets away from the casting object, as in real life. The angle button sets the visible area of the sun. Real Sun is visible in a cone angle of about 0,5º. A bigger angle mean a bigger sun, as well as softer shadows, which could be interesting for dawn or sunset scenes. A very big angle can be used to simulate sun light filtered by an overcast sky.
|Comparison between Directional (left) and Sun (right). Notice how, with a Sun light, shadows get blurred as the distance with the casting object increases.|
Arealight is a area light type that can produce soft shadows and its shape can be seen in reflective surfaces. The arealight shadows need to be sampled several times and interpolated to reduce noise. This type of light takes more time to be computed in contrast with point light types such as spot and point.
The area light size is controlled by the Size setting in the Blender Lamp panel. The rectangular shape option in that panel is not supported, although you can get a YafaRay rectangular arealight by scaling on axis in the 3DWindows.
When the Make light visible button is enabled, a rectangle in the size of the area light is generated, so that the area light gets rendered visibly. More lighting power is added as well to the scene.
When photon mapping is enabled, arealights cast photons. The Make light visible option only makes the arealight visible from the camera and in reflective surfaces. When pathtracing is used, the Make light visible option also creates caustics paths, although there exist an option to not trace caustics paths with path tracing as they tend to be extremely noisy ('none' option in Pathtracing settings, see 5.1.1).
Example of a rectangular visible arealight.
Other area light types:
Spot is a common point light with directional properties. Light color and Power settings work like in the other light types. Beam properties (angle and edge softness) are defined in Blender panels (light select. & F5) with SpotSi and SpotBl sliders:
First a camera should be created or exist in your scene. Lens angle and ortho scale must be configured in the Blender Camera panel (F9). Then select the camera and press Object/Light/Camera main button. The python UI will automatically change to show specific camera settings. There are four camera types in YafaRay: Architect, Angular, Orthogonal and Perspective.
This camera type works like a Perspective camera type, the only difference is that the vertical component of the perspective effect is neglected, so scene vertical lines are not convergent. Depth of Field settings are available for this camera type as well. DOF settings are explained in the Perspective/DOF section.
|Comparison between Perspective (left) and Architect camera (right). Notice the lack of vertical convergence in the Architect camera. Scene by Kronos
Example of an angular camera, used to create perspective distortion. Scene by Gabich.
A camera type that renders an orthographic (perpendicular) projection of the scene, without perspective effects. Camera only setting is:
Comparison between perspective camera (left) and ortho camera (right).
Perspective is the standard camera mode that simulates a lenses photographic camera with perspective effects. All settings available for this camera type are used to enable and configure the depth of field (DOF) effect. The depth of field is the distance that objects appear in focus. DOF settings are:
The DOF effect depends also on the render anti aliasing settings to get a nice blurred effect. First of all it is recommended to lower AA threshold a bit, but not set it to totally zero. Setting a high number of AA passes is also not really going to make all that much difference, the main smoothness factor that makes the most difference is really the amount of AA samples. A single pass with a high number of samples may be sufficient.