Luxus Pro Training: Orange Sky

MIBA

Hi,

i am following Bluebird´s Luxus Pro Training and i am having a problem with lighting.

My scene has:
- a cube
- a plane
- an UberEnvironment2

The parameters for UberEnvironment2 are:
- General > Tranforms > Scale: 1%
- Light: default values unchanged
- LuxRender Light > sky2 > gain: 0.0005

According to the training video the sky shoud render to white. Instead it renders to orange. What am i missing?

Thanx in advance

Herald of Fire

It's important to understand how lights work in Luxrender, as they're a very different beast to 3Delight lighting.

Firstly, the UberEnvironment doesn't really mean much when it comes to Lux. You could just as easily use a distant light as your sun/sky2 and get exactly the same results. UberEnvironment is a shader light and is therefore ignored by the engine so the only information being transferred to Luxrender is the extra settings you've applied.

Now, with that said, UberEnvironment has a serious downside when being used as a light source. That is to say that the rotation of the UberEnvironment is ultimately the rotation of the sun being cast. As this is likely set at the defaults (no rotation) the light being cast will hit the surface head on as if cast from the horizon.

The orange is because of the way Luxus handles skylights. The angle of the light is directly related to the colour of the light cast, and therefore the colour of the sky. This is to simulate sunset and sunrise in the real world. So in order to maintain a blue sky you'll want a decent elevation on your Luxrender light.

Edit: A quick example below. All that I've changed between the two images is the elevation of the light source. The direction remains constant as well as the type and intensity of the light. Notice how the 2nd image is much more red than the first.

MIBA

The sun is rising! :-)

That´s fantastic! Thank you for this very helpful information, HeraldOfFire! (Saw your edit, too)

I changed the X Rotate factor for the UberEnvironment2, and voila ...
I guess that X Rotate -90 equals noon an -180 would be sunset.

But what about that gain-factor and ... Okay, i see, there is much more to investigate and to discover for this caveman. ;-)

Herald of Fire

I'd still advise using a directional light as the base. In this way you can use the light camera view to ensure shadows are in the right place. Simply put the light in the scene, convert it to a sun/sky2 light in the same way you did for UberEnvironment and use the camera selection controls in the viewport (where it says Perspective View) to swap to the directional light.