Fog Volume
Coming out of Spring Break I am going into an entry of instruction regarding adding more detail. One way to add ambiance and character to an area or to help define light and space is with fog. Fog, like many other things, is easy to abuse. It looks great, you want to put it everywhere but if something is everywhere then it is no longer special. As with other elements, it should be seen as a single tool that works in concert with light, textures, objects, sound, music etc to make the user want to accomplish an objective. Fog attributes can be controlled via the Time of Day editor. You can create a Fog Volume via Rollup Bar>Objects>Entity>”Fog Volume” in the small browser window.
The Fog Volume is translated as you would other assets, so it can be moved and resized. It begins as an orb that can be moved into position like any other object.
The best way to work with an asset such as fog is to make it really stand out so that you can see what you’re working with, then once you have the right shape you can make more refined edits. Volume type is either 0 (round) or 1 (square). You can control the fog color, make it reflect the sky and existing light (UseGlobalFogColor), falloff, density, etc. By creating a volume with a greater Z (vertical) value and then translating the position a soft, natural effect that blends in with the environment can be created:
The effect is especially nice if you combine fog with variations in terrain, so that it sits in lower areas but dissipates or disappears in higher areas or inclines and slopes.
Water Volume
Non-contiguous water can be added by using the River Tool or by adding a Water Volume. This is also how to add waterfalls. To use a Water Volume: Rollup Bar>Objects>Area>Water Volume. To actually create the volume, click points defining the area, then double-click + right-click to end the creation process. You want to make sure that Follow Terrain (circled in red, below) is turned on so that the volume matches the ground surface. The process is simple and similar oto creating a polygon in Google Earth. From there you may edit parameters.
The first task is to assign a material for the water from within the material editor under Water Volume. You may rename materials to organize them as you see fit, but it is best to keep the first name as “water” or “ocean” so that if you are working with others and have different types of materials in a single folder, you will not have any confusion, as different types of materials have different attributes. For example if you inadvertently applied an ocean material to a smaller body of water you would likely get poor results and have difficulty refining it properly.
Obviously it looks sort of funky to have this clean shape in nature, but once you get the water to look right then you can make it fit properly. You can control just about any attribute you can imagine, starting with color to match the environment in a basic way and then adjusting other parameters for light, reflectivity, foam, ripples, refraction, caustics etc it’s pretty ridiculous. Depending on which material is used, the surface movement will be larger or smaller. Unless it is windy an isolated body of water would probably have less movement and surface detail.
It’s important to note that both the material you choose as well as the Water Volume itself have editable attributes. The material is edited in the material editor while the volume itself is edited with the parameters in the Rollup Bar, below. You can probably notice a reddish glow around our water volume. It’s a good idea to keep the glow outstanding in this way while you work the volume and the glow color, just so that you can see what you’re doing, and then tone down the glow after you’ve complete the final volume shape and see how it looks as a whole within the environment while in-game. I often work this way in Photoshop when working on textures, for example. Rather than simply looking at color-data I can see how warm or cool colors actually are by turning up the saturation now and then, just to compare, then cancelling that and going back to work. The same idea works here; you don’t actually want that much glow because it looks nasty and fake, but it’s a reference for what you’re doing at a given moment.
It’s easy to forget about another set of parameters when you get drilled in to what you’re doing. Don’t forget the material properties after you begin editing the volume properties, and vice versa. Once the general water volume is acceptable you can edit the shape to make it fit properly into your geographic area. “Edit Shape” under Shape Parameters. CTRL + Left Mouse enables the addition of more control points so that you have a more detailed shape to work with around your terrain. You simply grab individual points just as you would grab vertices in Maya or 3ds Max or a point in Illustrator. As usual this is criminally easy. It is not necessary to use fine detail when creating the shape of the volume; define its edges so that they cut into the surrounding terrain and the surface of the water will match the slope of the terrain.
As you can see as soon as you go in-game the water is already physics-enabled and reacts to stimuli such as projectiles, it reflects the environment etc. Remember to go in-game now and then to see that your fog isn’t unrealistic by being too thick or having an overly-saturated color. It might look good looking down from a bird’s eye view but when you get into your POV from the ground it may be overbearing. The same goes for water volumes. This type of thing is so impressive and easy to make that, at first, you may be tempted to turn all the ripples, reflections, caustics etc up to full-blast, only to look at them later and realize that you have too much going on and it compromises the integrity of the environment.
At this point in the semester we are a little ahead of schedule so I will break here and see about the best way to share levels with the instructor, then move on to Particles and Boids and visual dynamics in the next blog entry. After that will be Decals and Roads then, finally, ending the semester by making a new level from scratch (but using built-in textures and materials) and some insight and conclusions of the first part of this course.
Eric Chamberlain 