Scene:
The Lighting system depends on the Color or Luminance channel of your Sky material, assigned to your Sky object. You can simply drag and drop the Texture tag from the sky object to the link field in the userdata and set the proper Channel (Color or Luminance). The Position of the SkyLight object is connected to an other object. You could use any object for this, but the most suitable object is of course a sky object.
If you rotate the sky object, the Skylight object will rotate accordingly.
Icosohedron sphere:
An Icosohedron sphere is unique spherical object, which has one fantastic feature. This object is build up with uniform triangles, thus there is a really homogenous structure. It is a fantastic advantage for lights instances based on this object, but this sphere does not have a standard "spherical" UV map. We must solve this disadvantage by other way.
With an icosahedron sphere we can set two major settings, Radius and Subdivision. But the Subdivision settings has other influence like other sphere types. Subdivision is changed by 5 steps only. The system of our tool must properly transform the subdivision settings to the number of lights instances, it is really very important for the global lighting brightness settings.
Number of lights:
Instances of light are generated with the formula shown below:
Lights=Points=(Subdivision^2/5x4)/2+2, subdivision settings is automatically corrected to a step of 5...
Types of lights:
We can use two types, a standard omni light and a spot light as well. On both types we can adjust many settings and parameters, for example shadows (all types), contrast, specular etc.
Global Lighting settings:
In the system we set the global brightness only, the brightness of the instances are generated automatically with a formula as shown below:
Global brightness/((Subdivision^2/5x4)/2+2).
We can use two "cutting planes", too. We can set the position (%) and the falloff (%) of these planes. There is a horizon cutting plane and a side cutting plane. We can set the side cutting plane with a H angle setting (global) and an elevation angle. The Side cutting plane position and Horizon plane position are used in global brightness analysis too. This is used in the formula shown below:
(Global brightness/(Subdivision^2/5x4)/2+2)*Horizonpos*Sidecutpos.
The Horizon and Side cutting planes are not moved linear (changing of % settings), they are moved by next spline:
-1*(cos(x*Pi))/2 + 0.5
This is really very useful for linear masking of the lights instances.
These planes can not switch off lights instances, but they can set they color to 0, 0, 0 and these lights are not rendered. The render is a lot faster in many cases!
Info panel:
We can find here a adjusted global brightness information (include side and horizon cutting), sample brightness information etc.
Shadows:
We can use all the shadows types within CINEMA 4D, All the shadow settings that you need can be find here. We recommend you to use soft shadows. If you found some artifacts in your scene, adjust your Bias setting and shadow map settings.
Recommendations:
- Use cache map shadows option in the Render settings
- Use a HDRI map in your Sky material
- You can switch off the generate GI in the compositing tag on the Sky object.
- You can use more than one Sky object, use Compositing tags if this is the case!