Rendering, lighting and shading

Lights

The current version of PocketStudio support 4 light types:

Works on:PreviewHigh-quality

Physical skies are good to simulate outdoor lighting on a perfect day (with absolutely no cloud at all); one is added by default when a new scene is created.

Physical skies are procedurally generated; they are generated by the computer in real-time, using a set of physical parameters that describe its properties. By changing the values of these properties, you can control the look of this sky dynamically, in real-time. The physical sky can only simulate the look of perfect skies, skies without any cloud at all. For realistic looking skies (with clouds, etc.), use skydomes instead.

The physical sky is made of a sun and a sky. The sun and the sky are interdependent; the brighter the sun, the brighter the sky. Similarly the look of the sun in the physical sky model, depends on the sky. The hazier the sky, the larger the halo around the sun.

  1. Accessing the physical sky parameters: click anywhere on the sky itself in the viewport. This will display the sky’s parameters in the Property Editor panel.

    Clicking on the sky in the Viewport to access the sky’s parameters only works when the Viewport is in the preview rendering mode. It won’t work in the high-quality mode. To switch from one mode to the other, press the F2 key.

ps docs physicalsky

  1. Physical sky parameters: the physical sky parameters are grouped under the Skydome properties label in the Property Editor. Change the values for the Global Intensity, the Solar Azimuth or the Solar Elevation and watch the lighting change in the Viewport. Changing the Solar Azimuth value is particularly interesting: see how the shadow cast by objets changes on the floor.

For a detailed description of the procedural sky parameters, click on the parameters below.

Should be checked. When this box is unchecked, the image-based skydome is used instead.
Changes the brightness of the sun which itself influences the brightness of the sky.
Defines how hazy the sky is. Higher turbidity values tends to make the sky greyer. Turbidity simulates the effect of large particles in the atmosphere such as those associated with pollution over cities.
Used in the preview mode only. It simulates the action of light bouncing off the floor.
Controls the height of the sun is in the sky. This value can vary in the range 0 (horizon) to 90 (zenith) degrees
Move the sun around. This value can vary in the range 0 to 360 degrees.
The bigger the value, the bigger the sun and the brighter the sky. A value of 1 gives the sun a size close to that of our sun.
Defines the color temperature of the sun. Our sun is typically 5900 degrees (Kelvin).
Modifies the brightness of the sun as it appears in the viewport, without influencing its contribution to the sky overall brightness.
Modifies the size of the sun's disk without influencing its brightness or contribution to the brightness of the sky.

Works on:PreviewHigh-quality

The skydome is somehow similar to the physical sky. You can look at it as a large hemispherical light placed onto the scene. Though rather than being procedurally generated as in the case of the physical sky, the appearance of a skydome is defined by either a constant color or by an image. Such images are called environment maps or HDRIs. They typically have a 2:1 ratio and are stored in floating point image file formats such as EXR or HDR. HDRIs are generally captured by shooting real skies or real environments typically using chrome balls or fish eyes lenses. Free HDRIs can easily be found on the web (see the great website HDRI Haven for example).

  1. Uncheck the User Generated Skydome parameter from the physical sky dome properties
  2. Drag and drop an HDR image on the sky in the viewport in either HDR or EXR format.
  3. Adjust the skydome properties: change the values of the skydome properties to adjust its contribution to the illumination of the scene.
  4. Switching the skydome off: to switch between the skydome and the physical sky, check the User Generated Skydome parameter in the Property Editor.

ps docs HDRI light

Should be unchecked. When this property is checked, the procedurally generated skydome is used instead. If you use a texture for the environment rather than a constant color, the image needs to be in either the HDR or EXR format.
Controls the overall contribution of the skydome. The higher the value, the brighter the scene.
You can rotate the skydome aroud the Y-axis. This is somehow similar to the Solar Azimuth property of the physical sky model.

Works on:PreviewHigh-quality

Distant lights are one of the most basic types of light in computer graphics. The lighting of our sun can be simulated with a distant light.

ps docs distantlight

  1. Create a distant light: click on the light icon located on the Toolbar. New distant lights are added at the origin of the scene.

  2. Change the light direction: select the light, press the e key to display the rotation gizmo, then rotate the light.

    Changing the position of the light can be convenient to reposition the light gizmo somewhere else in the scene but has no effect on the lighting of the scene itself. Similarly, scaling a distant light can be useful to see its gizmo better in the viewport, but doesn’t impact the lighting.

  3. Adjust the distant light properties: change the light properties such as its color or strength.

The color of the light
The global intensity of the light

Works on:PreviewHigh-quality

The angular size property is only in effect in the high-quality rendering mode. This value is expressed in terms of angular size (in degrees). The distant light is in fact considered like a small disk whose size is defined by this property. The larger the value, the bigger the disk. As the size of the disk increases, the distant light acts more and more like an area light and soft shadows can thus be produced.

ps docs distantlightsoft

Works on:PreviewHigh-quality

Light in the real world is always somehow emitted from the surface of an object. Consider for example the sun, the filament of a light bulb or the sometimes very large surface of floodlights used in photoshoots.

When 3D objects emit light, they behave as area lights. Area lights are useful to create soft shadows as depicted in the example below.

ps docs arealight

  1. Select a 3D object: select or create an object you wish to act as an area light in the scene.

  2. Set the object’s material Emissive Color parameter: create a new shader if necessary (see Materials). Adjust the value of the material’s Emissive Color and Emissive Strength parameters to control the color and strength of the emitted light respectively.

    Change the area light scale: the contribution of an area light depends on the value of the Emissive Color and Emissive Strength parameters but also on the size of the object emitting light. Imagine two area lights with the same emissive color and strength; the second one is twice as large as the first one. As a result the second light will emit twice as much light in the scene than the first one and will cause the scene to be brighter as depicted in the example below.

ps docs arealightsize

  1. Turn the diffuse and the specular off: you can turn the object’s shader diffuse and specular contribution off (set Dielectric F0 to 0, Roughness to 1 and Base Color or Diffuse Color to black) to have a purely emissive object.

Make an area light invisible to camera but visible to everything else (shadow, reflection, indirect diffuse rays, etc.)

Future versions of PocketStudio will have a visible to camera property attribute to control whether an object is visible to the camera rays while staying visible to other ray types (such as a shadow rays). This feature is not yet available in this version, however, you can achieve a similar effect using the following method:

  1. Select the geometry acting as an area light.
  2. Assign a shader to the selected geometry if none is assigned yet.
  3. Type the word ethereal in the text field of the shader name parameter.
  4. Set the shader parameters as usual (set the Emissive Color property, etc.).

XX TODO INSERT EXAMPLE OF EMISSIVE, BLOCKER, FILL REFLECTOR XX

This technique can be used to create blockers (which are useful to make parts of the scene darker), reflectors like those used on photoshoot to create a bounce effect for fill light, or turn an area light invisible to the camera.

Shadow artifact on animated objects

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How can I make the the scene completely black?

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How do I create soft Shadows?

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Can I create a point light?