Quick Cityscape

[robcat2075]

Cubes randomly scaled, Fog, and AO.

 

[Tom]

Looks cool...!

[robcat2075]

Simple grids added for window details.

[Tom]

What sort of Ambiance Occlusion are you using in that scene?

[Rodney]

Nice.  Does this mean you figured out how to do the random values confined to patterned areas?

[robcat2075]

13 minutes ago, Tom said:

What sort of Ambiance Occlusion are you using in that scene?

There are really two light sources.

The AO is set to 50% intensity and the sunlight ("Key") is set to 75%

[robcat2075]

3 minutes ago, Rodney said:

Nice.  Does this mean you figured out how to do the random values confined to patterned areas?

No, these were manually randomized.

I do recall making a way to get a random value to set once and stick in a chor. That could potentially be used to drive the building heights but would be too random for this scene where I wanted to have taller in back and shorter in front.

[Tom]

neat...thanks!

[Tom]

How would you describe the difference between "Ambiance Global" and "Radiosity"? It seems like there is a bit of overlap in their functioning...

[robcat2075]

9 hours ago, Tom said:

How would you describe the difference between "Ambiance Global" and "Radiosity"? It seems like there is a bit of overlap in their functioning...

There is some similarity in appearance, although the process is quite different.

Here is a test scene. It is an open-top box with a sphere inside it. A single kleig light is above and behind the box. The camera is inside the box, pointing toward the sphere and back wall.

 

 

A conventional render from the camera view gives this result. Every point in the scene is either illuminated by the kleig light or is black, for lack of illumination.

 

Global Ambience (AKA Ambient Occlusion) simulates an infinity of kleig lights from every possible direction. This all-over light reaches more parts of the scene; the surfaces that are more exposed to it are more illuminated and the surfaces that are more "occluded" from it are darker. Some surfaces like the bottom of the sphere and the area below the sphere are still completely untouched by this light and remain black.

Global Ambience ON, kleig light OFF:

In both of the above cases, if a point is not directly exposed to some source of light, it is unlit and black.

 

Radiosity (other programs call this "Global Illumination") works by calculating light that bounces off surfaces in the scene, as real light does.

The blue wall, which is completely hidden from the kleig light , is still illuminated by light bouncing off other surfaces in the scene. Light bouncing off the red and blue walls spill some color onto nearby surfaces. The bottom of the sphere, although cut off from direct light, is illuminated now.

Global Ambience OFF, kleig light ON, Radiosity ON:

 

This PRJ has the three chors above. To render them properly, you'll need to do Tools>Options>Rendering>Use Settings from>the Camera

AOvRadDemo005.prj

[Tom]

Wow..fantastic answers. I can't wait to study and test this!

Thanks!

[robcat2075]

In the Radiosity example, I set the Intensity parameter very high...200... so that the effect could not be overlooked.

Lower values are probably more typical in careful lighting situations.

 

This compares several Intensities. Note that a 0 intensity looks just like a conventional render.

The bottom row is the same images with a 1.8 gamma applied. These fine adjustments are where you want to know your monitor is carefully calibrated and that your audience's monitors are so also... which we never know!

 

 

 

 

[robcat2075]

Cityscape with AO, Fog and Radiosity. The Radiosity is a very slight effect in this case.

[Tom]

Here is a comparison. The Radiosity version is a bit more washed out...