1. Interpretation of specular and shininess reflection

2. Interpretation of transparency of image textures

3. Implementation of the GrinClonerNode behaviour

• CPU (Twilight) implementation: repeats objects only into first quadrant
• GPU (Flux) implementation: repeats objects into all four quadrants

4. Only in the Twilight light light model the additional function of getReceivedPower, getReflectedPower, getTransmittedPower, getAbsorbedPower, and getHitCount are implemented. See: More light model functions... beyond getAbsorbedPower

5. The twighlight model only handles skies with sky-shaders as light sources. Hence, the cloud texture does not act as a light source. GPUFlux handles any sky as light source, independent of the shader it uses. This allows the user to create its own sky light source. As a consequence, the cloud texture also acts as a light source, resulting in the dominantly blue lighting on some scenes. This was a deliberate choice to make the sky objects more flexible.