UDK: Further Research

To continue on with the tutorials I am now looking into environmental lighting. In previous projects I was able to change the time of day, but did not try any other forms of lighting.

Building Lighting

When objects are added or manipulated within your scene lighting will need to be rebuilt. This is because UDK needs to bake lighting into the scene for it to be updated. A warning will appear when play testing the game.

To build or re-build lighting simply click on the left bulb on the toolbar at the top of the screen, which is highlighted in the image below. Right clicking the right-hand bulb will give a drop down-menu, which enables the user to change what quality the lighting will be built with.

 Lighting within a scene
 

To navigate to the scene browser, go to
View > Browser Window > Scene

Within the scene browser all objects within the scene are shown.

DefaultPhysicsVolume: This creates the physics for the level, allowing the implementation of collision meshes, particles, animation events and kismet events.

DominantDirectionalLight: This is main ambient light in the scene, simulating sunlight.

ExponentialHeightFog: This type of fog is dependent on the player's altitude within the level, the lower the player is, the denser the fog.

Interpactor: This is the sky dome, which shows the clouds.

LightmassImportanceVolume:This tells UDK what are the most important areas to be rendered at the highest quality, for example the playable regions of a map.


Dominant Directional Light

The dominant directional light helps create the scenes main ambient lighting. It is customisable by locating the directional light within the scene and double clicking on it.

Within this there is the possibility to change the colour of the dominant light. This example shows the main lighting with a blue tint.

The light shaft check box turns on and off light shafts, which create a more believable scene by using rays of sunlight to shine through objects.

Without light shafts

With light shafts

 The light shaft colour can be changing by using the bloom tint to the required colour, this will change the sun's rays will be when shining on the player. In this example the bloom tint has been changed to yellow.

There is also the ability to change the suns direction, which in turn will affect where shadows fall within the scene. This can be done by rotating the dominant directional light within the scene.

Adding Lights

It is possible to adding lights by holding 'L' and left clicking within the scene, this will place a point light directly where you click. Though it is possible to add actor lights by going to
View > Browser > Windows > Actor Classes

They are found within the Lights > Spotlights tab. They can be accessed by dragging the light into the scene.

The lights work in a similar way to the dominant directional light, with the ability to be moved and rotated which will affect where the lighting is directed.

Environmental Colour

Environment colour controls the overall colour of the shadows within the scene, used to change the ambiance. To do this go to
View > World Properties Then open the lightmass tab.

Within the image it is possible to see the contrast between the yellow point light and the blue environment colour. This is best demonstrated on the tree trunks and ground. It is possible to edit the intensity using the environment intensity slider.

Fog

UDK allows for fog to be created and edited within the actor classes tab, the same location as the spotlight location, as well as the scene window.

The first example is exponential height fog, which uses the direction of the dominant directional light to blend two coloured fogs. The colour of the first light is based on the inscattering light. The other colour is based on the opposite light colour to the inscattering colour.

By increasing the fog height falloff and start distance it is possible to change how dense the fog is, and how much vision the player would have.

The fog density: How thick the fog is. It is best to keep this number low, as too much starts to look unrealistic.

Fog height falloff: How dense the fog is at lower altitudes.

Fog opacity: Controls how dense the fog is at maximum viewing distance.

Start distance: Determines when the fog begins in relation to the distance from the player.

To toggle fog hit 'F', which is useful when editing a scene which requires full vision of the environment.

There is also height fog, which does not include the inscattering and opposite lights. This can be found within the actor class.
View > Browser Window > Actor Class

 

Changing The Skybox

To change the existing skybox texture first select the skybox within the viewport and press F4. This will show the available options for editing the skybox. Search for materials, which will bring up the rendering option for the skybox.

Click on the magnifying glass to search the content browser for a suitable skybox to replace the current one.

The available skyboxes will be located by searching "sky" in the content search-bar and ticking the material instances box.

Once this is complete select the appropriate skybox and minimise the content browser. Locate the existing skybox properties and click the green arrow next to the magnifying glass previously pressed.

This should change the existing skybox into the one selected within the content browser.