octane DAYlIght

Octane has a very powerful and detailed daylight system. It is a type of light you will use very often for your outdoor render. From here you can adjust the sun and sky and give various effects. It also works very efficiently as integrated with other environment lighting "HDR / Texture Environment".

You can also create Daylight by selecting "Light / Octane Daylight" from the object menu of Live Viewer. If you select Daylight, "Octane Daylight" object and "Daylight Tag" appear in Object Manager.



transform operatIons of the DAYlIght

Transform from the viewport or FROM THE CINEMA 4D's ROTATION COORDINATION TAB

After you create Daylight, you may want to transform the light according to the nature of your scene or your purpose. Probably the first default transformation will not work. First of all, when we say Transform, we mean only Rotation value. In daylight, position and scale have no function. Octane Daylight actually uses Cinema 4D's "Infinite Light", but with use of  Daylight Tag, the features of the infinite light are canceled. However, you can change the light as desired because the rotation on the scene is a global value. To do this, first choose Octane Daylight and rotate your light object using the Cinema 4D rotate tool from the viewport or from the "Coord." tab. What is important here is the rotation value "R.P". You can use this to change the elevation of the sun. Thus you can create all other time intervals with day and night. You can also use the value "R.H" value but it is recommended that you leave the default because this value also corresponds to the "North Offset" option in Daylight and we will explain this option in the Daylight Settings.



settIng up SUN's latItude & LONGITUDE from the SUN TAG

Daylight's location can also be done with the help of Sun Tag. So you will be using more realistic lighting settings of your sun. Sun Tag is off when you first create Daylight. To change this, go to the basic tab and check "Enable". You can then adjust the Latitude & Longitude settings from the Tag Tab.




DAYLIGHT & ENVIRONMENT PRIORITIES

If you create a Daylight or Environment light (HDR or Texture) at the same time in Octane, the Plugin has some priorities. For example, let's say you created one Daylight and then you created one HDR environment. In such case, the priority on the scene will always be Daylight. However, HDR will not be used unless you enter the Daylight settings and select "mix sky texture". Or, if you create 2 separate HDRs and Texture Environments, the priority will be "Object Manager" based on the sorting (eg HDR environment over Texture Environment). The following table shows the priorities of the lights.




OCTANE DAYlIght settIngs

Now let's take a closer look at the options of the Daylight Tag


TYPE

There are 2 options here: "Primary Environment" and "Visible Environment". If you want to use two separate environments in Octane, you can set one backplate and use "Visible Environment" in this menu. What does it do? Let's say you want to change the default environment of Daylight (we will not be using HDR for now). For example, instead of the blue sky, you think of a procedural sky. First of all, create a Texture Environment light from LV other than the existing Daylight. Select "Visible Environment" from "Type" of Texture environment options and select "Backplate" from the options. Immediately the Daylight Environment becomes invisible. Instead, you will see the default white color of your Texture Environment.

It is easy to define the texture for the backplate. You can go to the Texture menu and assign the type of texture you want. When the Visible Environment is active, three options are set. Now let's explain these options:

Backplate  

You can see the texture you defined as Visible Environment by activating this option. In the picture below you can see the normal and Visible Environment difference. As you can see, when the Backplate is active, the normal daylight environment is replaced by a texture environment.

Info: The Visible Environment only functions as a backplate and the contribution to overall illumination is minimal. You need to use HDR for this.



REFLECTIONS & REFRACTIONS

The visible environment will override the daylight environment when calculating reflections for specular and glossy materials.



TURBIDITY

The full name is "Atmospheric Turbidity" and it's an environmental term, which is the appearance of the atmosphere as hazy or turbid, due to condensed micron-sized solid and liquid particles (aerosols) in the air of a particular area. In Octane, it changes the distribution of sunlight and the sharpness of the shadows. A low value creates sharp shadows (like on a sunny day) and a higher value diffuses the shadows similarly to a cloudy day. You can also create a beautiful clear sky or a pessimistic atmosphere with this option. Turbidity differences shown in the picture below.  



power

The Power slider can be used to adjust the strength of the light. This can affect overall contrast and exposure level of the render.



north offset

The North offset can be used to adjust the actual North direction of the scene. This is useful for Architecture Visualization to ensure the direction of the sun is accurate to the scene. You can also change the North Offset by playing the "R.H" rotation of the light from the viewport.



SUN SIZE

From here you can set the radius of the sun. If the radius is big, the shadows appear soft. Or vice versa.



new model

This specifies which daylight model to be used as the current environment. The old daylight model lights a scene with basic spectral radiance as the sun moves over the horizon at a relative distance from the object. The new daylight model is used to simulate full spectrum daylight providing more sky color variation as the sun moves along and bearing shorter rays as the sun moves closer to the normal plane. The Nishita Light Mode implements atmospheric scattering based on the Nishita Sky Model and displays the variations of color which are optical effects caused by the particles in the atmosphere.

Info: You can't change the color of the sun and sky in Nishita Model. Since it is a physical model, both sun and sky colors depend on the sun's rotation and atmosphere scattering. The reason for changing the colors of both the sun and the sky is because the particles in the atmosphere (such as air molecules, aerosols) scatters the sunlight.


sky & SUN COLOR

Here you can adjust the sky and sun colors.


mIX sky texture

This option is for using Daylight Sky with HDR / Texture. When activated, your other HDR / Texture environment begins to illuminate the scene, but your daylight sun keep its location and other features. Now let's explain how this option works in a few examples.

Mix Daylight Sky with HDR/Texture Environment

Create one HDR or Texture Environment. Define the image for HDR or Texture and play with the settings if necessary (you can look at the next section for the HDR / Texture Environment topic). Activate "Mix Sky Texture" from Daylight. As you can see in the picture, the HDR environment now works with the Daylight system. But in the picture it is necessary to match the daylight sunshine with the HDR sun, because the current lighting is totally wrong. In the next section we will explain how to fix this situation.



FIX & MATCH Daylight SUN ACCORDING TO THE HDR SUN

The way to match the daylight sun with the HDR sun you see in the picture above is to manual adjust by playing Daylight with both from the viewport rotation (H.P. and R.P) and the north offset. Once you do this, you can child the Daylight to the HDR environment. So the your daylight rotates with in every rotation of the Sky object. This is the most practical way.



As you can see in the picture below, daylight sky sun is in a match with the HDR sun. There is no incorrect lighting as in the previous picture. Daylight Sun will follow in every rotation of the HDR sky. You can also play with the Daylight Tag settings (such as power and turbidity) to better match the light.



Importance samplIng

Enables quicker convergence (noise reduction) for certain areas so the sample rays that resolve to the important areas more often than unimportant areas. This means the ray tracing is more efficient as it is not wasting time on rays that do not contribute much to the overall image quality. Due to the added complexity this will reduce the Ms/sec of rendering, but each Ms will be more effective, therefore resulting in a higher image quality in less time. Importance sampling is enabled by default.


ground color, Ground start angle & ground blend angle

When you first create daylight, the color of the ground is black. You can set the color of the ground. Ground Start indicates where to start. Ground Blend Angle is used to mix the sky with the ground.



DAYlIght MEDIUM settIngs

It is used to give a fog to the daylight system. You can create very nice atmospheric fog because it applies to the scene in general. This fog is not a fake fog but Volume Medium. It interacts directly with any lighting in the scene. Since this topic is wide, we will explain more detail in the "Volumetrics" section.