Edit Water: Master Guide to Water Physics in AOE3
From AgeofWiki
Please note: this article contains images and references using Reyk's Editor Mod N3XY for TWC/TAD.
This is a more quantitative guide to creating handsome, natural-looking shallows and shorelines in AOE3 and its expansions. Use this as a supplement to the Water tool and Edit water tool basic guides.
| Table of contents |
General Tips
Water in AOE3 is a 3-dimensional terrain type. One may view it like a pliable solid: it has a surface, a body, and a floor or base. Each water type has a unique set of characteristics for each functional "part" of the water type. We can use these properties to create convincing shallow water effects, where players can see terrains and objects below the surface, and likewise conceal items and terrains by using the reflective properties and turbidity of the water type.
Discovering the Properties of AOE3's Waters: Setup
The experienced scripter or modder can easily extract the exact light-sensitive characteristics of each water type from the proto files and art.bar files (alpha, Fresnel diffraction and reflection coefficients, surface wave equations). However, the raw numbers do not tell you how the water will actually look in your scenario. They also do not tell you how different lighting effects will change what you see. To test the colors and opacity thresholds of the various water types, it is helpful to use a lakebed with graduated depths and a neutral white terrain bottom, as shown. The resulting water body shows progressively darker bands with deeper depths, until it reaches a maximum value, or until the opacity threshold depth is reached and masks the bottom terrain.
The standardized-depth lakebed shown here has depths ranging from 0.5 units to 3.0 units in 0.25-unit stages. The Axe Rider stands at the deepest depth for which land units may pass (0.75 units). A gold crate marks the 1.0 depth zone, and an additional 2 gold crates mark the 2.0 depth zone (just off-screen).
To make a standardized lakebed, use the Cliff tool to create a set of exact-height cliffs or troughs, one for every 0.25 unit change in depth. Make them off to the side, so that you can sample them with Elevation sampler tool and then set the elevations in depth zones from 0 to perhaps 3 or 4 map units below the surface.
Standing Water: Tint
One of the first things you will notice about the various water types in AOE3 and its expansions, is that most water types are tinted with a characteristic hue, independent of their reflectivity or translucency. This hue changes as your eye travels from near-field to far-field. The main hue is that which you see when you are looking directly down upon the water from above. The secondary hue is that which you see when you are looking at the surface of the water from further away, or from a more angled perspective. Seeing this effect requires a higher graphics setting as it is a secondary mathematical transformation, but is simplified in-game so that most secondary tint is bluish, like the sky, to mimic the greater reflection of the sky color when looking at water surfaces from a distance.
To find out the particular hues a water body will assume under a particular lighting, it helps to use the graduated lakebed with a reflective terrain. Shown below is a sampling of two different TRANSPARENT water types illustrating their wide variation in hue, intensity, and value. Lower left: Constantinople (Istanbul HC) water. Upper right: Amsterdam HC water.
OPAQUE water types may have even more intense tints to create the illusion of greater depth even at shallow depths. Lower left: Texas Pond. Upper right: Cinematic Ocean water. Notice that although both of these water types remain translucent until they reach a depth of 2.5 units, they are quite intensely tinted.
Standing Water: Opacity
Most standing water in AOE3 is opaque, so that the deeper parts of the water bodies are appropriately concealed as in nature. This also allows large bodies of water to have reflective properties that would otherwise be obscured by objects and textures under the surface. For instance, we cannot see the ocean bottom in real life, instead what we see is a mostly opaque body of water with a bluish tint and reflections of the sky's gray or blue color. For those regions of the New World where one can see structures on the sea floor, a few water types have been made purposely transparent but with a depth-dependent tint, such as Caribbean Coast and Ceylon Coast. These are tropical reef areas where you can normally see quite a ways down in the crystal-blue waters; they aren't meant to represent open ocean, where great depths and flourishing plankton and algae tend to make the water opaque. Lastly AOE3 has a few water types that are exceedingly opaque, meant to represent turbid or muddy water. Yellow River Flooded, Bayou, and SPC Bayou, for instance, are completely opaque at depths where other opaque water types are still translucent.
Top to bottom: Yellow River Flooded, NW Territories, and Bayou. Each of these water types is strongly tinted and highly opaque.
Standing Water: Reflectivity
Reflectivity is a property of water types in AOE3 independent of their basic color. Each water type in the Editor has a characteristic surface reflectivity that makes it suitable for a variety of effects. For instance, a water type with gentle or no waves, vivid blue color, and high surface reflectivity is an excellent choice for making small ponds in warm temperate climates. A very calm water type with a strong gray or brownish tint, high transparency, and low reflectivity is great for making stagnant pools or sluggish "black water" rivers in steaming jungles of the upper Amazon.
Some water types are fairly transparent and have low surface reflectivity, but have the special appearance of being illuminated from the side. These water types will appear to have sparkling whitecaps or ripples (Paris, London, Coastal Japan) or waves that cast shadows even when lit from directly above, as if by a setting or rising sun (Deccan Plateau, India HC, China HC). Use these water types with evening or sunrise lighting settings for a dramatic effect. Conversely, these may not be suitable for underwater buildings and events, because the sidelit surface sheen makes it hard for players to see what's going on under the surface. For more information on the effects of lighting on setting moods and bringing out unusual water effects, see Intermediate Guide to Lighting.
These three water types have the SAME basic hue but because of their differing surface reflective properties, they appear very different in the same overhead lighting. From right to left: Great Plains Pond, Hudson Bay, Seville HC.
Viewing a body of water from a different angle, or using a lighting style with a different angle of incidence, can dramatically change the appearance of water types. Here, the camera angle changed from 90 degrees (directly overhead) through 47 degrees (default pitch) to 25 degrees angulation. The water type New England Coast is very reflective when viewed from a low angle, but seems darker at mid elevation, and from above it appears almost matte royal blue.
For more information on lighting angle of incidence, please see Intermediate Guide to Lighting.
Standing Water: Wave Patterns and Wave Animations
This section under construction. Briefly, several water types have associated with them a characteristic background wave pattern, and may also have a shoreline wave animation such as breakers. It is worth remembering which types have animated breakers or foam, so you can use them properly when designing and testing scenarios at low graphics settings. Breaker and foam types of wave animations may cause lag on some people's computers which you won't detect if you are in low graphics mode. This can cause some problems for your scenario's play value or cause rolling breakers to appear where they shouldn't, i.e. streams and ponds.
See the table below for the wave types associated with each water type.
Rivers: Opacity, Tint, Reflectivity, and Vector
River water types also have their own unique values for these attributes. All river water types are opaque with a variable translucent zone. All are highly reflective, and share the same surface wave pattern except for Yellow River which has a calmer surface. The diagram below shows three representative river types and the methods used to determine hue, opacity, and surface reflectivity.
These three rivers have different depths of opacity, water color, and surface characteristics. The large red arrow marks the boundary between opaque and translucent water. Note that rivers placed with the River tool have a characteristic innate depth, and that for instance Andes rivers are naturally shallower than their default opacity, so one can see the riverbed terrain. From top to bottom: Andes, Amazon, Deccan.
In addition, river types also have vectorized flow animations that follow the direction and order of way point placement using the River tool.
Table of Water Characteristics
| Water Type | Reflectivity | Wave Pattern | Opacity | Base Color | Native Depth | Notes |
|---|---|---|---|---|---|---|
| Amazon River | High | River | 2.5 | 3 | ||
| Amazon Basin | Low | B | 2.5 | 3 | ||
| Amsterdam | Matte | B | Trans | 2.5 | ||
| Andes | Low | River | 3 | 2 | ||
| Araucania CC | Low | C + breakers | Trans | 3 | Same as Araucania SC | |
| Araucania NC | Low | C + breakers | Trans | 3 | Same as California/Carolina/Caribbean/Ceylon | |
| Araucania SC | Low | C + breakers | Trans | 3 | ||
| Atlantic Coast | Moderate | D + breakers | 2 | 3 | ||
| Bayou | Low | D | 1 | 0.75 | ||
| Bayou SPC | Low | D | 1.25 | 0.75 | ||
| Berlin | Low/Matte | E | Trans | 2.5 | Same as Iroquois HC | |
| Borneo Coast | Moderate | D + breakers | 2.25 | 3 | Same as Borneo Water but with breakers | |
| Borneo Water | Moderate | D | 2.25 | 3 | Same as Borneo Coast but no wave anim | |
| California | Low | C + breakers | Trans | 3 | Same as Carolina, Caribbean, Ceylon | |
| Caribbean | Low | C + lg breakers | Trans | 3 | Same as California, Carolina, Ceylon | |
| Carolina | Low | C + breakers | Trans | 3 | Same as California, Caribbean, Ceylon | |
| Ceylon | Low | C + breakers | Trans | 3 | Same as California, Caribbean, Carolina | |
| China HC | Low | B | Trans | 2.5 | Side-light effect | |
| Cinematic Ship Ocean | Matte | Special | 2.5 | 3 | Drifting waves animation | |
| Coastal Japan | Low | C + breakers | Trans | 3 | Side-light effect | |
| Constantinople | Matte | B | Trans | 2.5 | ||
| Deccan | High | River | 2.5 | 3 | Side-light effect | |
| Great Lakes | Moderate | D | 2.5 | 3 | ||
| Great Lakes Ice | Low/Mod | B scaled | 2.5 | 3 | ||
| Great Plains Pond | Moderate | D | 2.5 | 3 | ||
| Hudson Bay | Moderate | D + sm breakers | 2.5 | 3 | ||
| India HC | Low | B scaled | Trans | 2.5 | Side-light effect | |
| Iroquois HC | Low/Matte | E | Trans | 2.5 | Same as Berlin | |
| Japan HC | Low | E | Trans | 2.5 | Side-light effect | |
| Lisbon | Matte | E | Trans | 2.5 | ||
| London | Low | B | Trans | 2.5 | Side-light effect | |
| New England Coast | Low | B + breakers | 2.5 | 3 | ||
| New England Lake | High | D | 2.5 | 3 | ||
| NW Territory | Low/Mod | D scaled | 1 | 3 | ||
| Pampas River | Moderate | River | 3 | 3 | ||
| Paris | Low/Mod | B scaled | Trans | 2.5 | Side-light effect | |
| Saguenay Lake | Moderate | D | 2.5 | 3 | ||
| Seville | Matte | B | Trans | 2.5 | ||
| Texas Pond | Moderate | D scaled | 3 | 3 | ||
| Yellow River | High | D | 1 | 1.1 | ||
| Yellow R. Flooded | High | D | 1 | 3 | ||
| Yucatan | High | D + lg breakers | 2.5 | 3 | ||
| Yukon River | Low/Mod | D | 2.5 | 3 |
Further Applications
For more tips and walkthroughs on Underwater terrain and objects, see the tutorials on Underwater Trade Routes and Guide to Underwater Buildings, Units, and Terrains.
