How to Change the Appearance of Terrain In-Game

Article written by NowhereT
Published on 11-24-2011; updated on 07-05-2016

As most scenario designers know (at least, those who frequent the SD&M forum probably all do!), there is a clever trick in the editor which involves creating and removing bridge sections to add patches of walkable water. The trick requires trigger effects to add and then remove (often in the same trigger) a bridge middle section, which leaves a “footprint” of walkable water.

Due to restrictions of the game engine, scenario terrains cannot be altered in-game, only in the editor. However, their appearance can be changed. With a bit of creativity, there are a lot of different effects which can be achieved. Some of my personal favourites are listed below:

Building a Bridge In-Game

Bridges, when placed in the editor, are passable only to land units – boats cannot cross them. This means that if bridges are placed across a river, boats cannot travel up and down it. Not only is this unrealistic, but it can also add limitations to a scenario – leading people to favour the use of fords (made out of shallows) or transport ships to get units across water.

However, by using a path of shallows (which are passable to ships and land units), a clever trick can be utilised to have a bridge in game which can be crossed by boats and by land units.

Firstly, create a path of shallows in the editor. This will be the terrain that the game recognises to be used, thus allowing ships and land units to cross it, like this (screenshot from game mode, not editor):

Next, “hide” the shallows by placing and removing bridge middles. The image below is what the first trigger looks like. In game it looks like this (two images), but if you ensure the player has no units around (or cartography is disabled/allied units are not present) you can hide the mechanism from the player.

Finally, create a bridge using triggers (the “place object” effect) across the path of shallows at, say, 9 seconds into the game.

Voila! A walkable, sailable bridge!

There are a few alterations to this effect, which are more clearly explained in these two tutorials (1) and (2). The first tutorial is mine, the second is by Den Cekke. The two are very similar; we coincidentally uploaded separate tutorials within days of each other. I believe Den Cekke’s tutorial may been removed from the blacksmith so the second link may not work. His tutorial was much the same apart from using rotated cliffs to make the water unwalkable and placing bridge foundations, allowing the player to build the bridge themselves.

If you wish to delay the construction of the bridge, like in the pictures it is worth blocking access to that patch of terrain for land units. Den Cekke used invisible cliffs, I would probably have suggested trees along the shoreline. Both can be removed by triggers so it’s your choice, although I believe trees along the shoreline are preferable since rotated cliffs are also impassable for boats.

Now, you have a path of shallows across the river which cannot be accessed by land units. So, when the time is right for your scenario, you can use triggers to remove the obstacles and place the bridge – thus providing a physical way of crossing the river (by removing the objects which were in the way) and a visual way (a great big bridge).

Den Cekke also suggests using the “place foundation” effect rather than the “place object” effect if you wish to have your villagers build the bridge as part of your game. Naturally, this only works if you have villagers, so be warned if you fancy this method in your RPG.

Floods and Frozen Lakes

The walkable water described earlier is a nice visual effect. Two of the examples of it I’ve seen in the blacksmith are Alexandergreat3’s animated waves and Silver Serpent’s flooding of a moat. These two examples are again visual only (they don’t change the characteristics of the terrain as created in the editor) and both can be broken if units get in the way of trigger-created bridge sections, so be sure to take precautions against this in your own creations.

Another example is making a hole appear in the ice over a frozen lake, as demonstrated here. A simple trigger can be added which will kill units which enter the “hole”, so while the game recognises the terrain as passable, the player will not be able to treat it as such. Again, this is not infallible – units which get in the way of the bridge section you need to create can ruin the effect.

Magical Islands

One effect I successfully achieved a few months ago (and then lost the scenario of!) was creating an island in-game. The method is similar to the bridge technique described earlier, but it uses bridge ends rather than bridge middles. Bridge ends, when placed by triggers, create a small patch of desert sand. A few of these combined can create a nice little island; I used mine to house a mythical soothsayer and his yurt.

To achieve this effect you will need to create your island in the editor – ideally with no elevation changes and preferably quite small. You also want to ensure that there are no objects which would look out of place in water – no trees, for example, but rocks may be OK.

You then need a trigger to disguise the island; place and remove a few bridge middles to cover the area in what appears to be water (the bits which were initially land will still be treated as land by the game). Then, whenever your storyline requires it, fire a trigger which places and removes bridge ends over the patch of land which represents your island – thus changing the terrain’s appearance to desert sand so the player can see the previously invisible island. You can then also use triggers to add trees, rocks, units or anything else that you like. I tried it with a renamed berserk (my “soothsayer”) using newIdea’s invisibility cloak which works since the game still treats that patch of the map as land, not water, so the ram can happily hide on the same tile until you want to reveal your units.

Again, there are problems with this technique – since the land never actually disappears, you may want to prevent the player from finding that it is impassable to boats. A suggestion would be to add rocks or trigger-induced gusts of wind to keep boats away until you want to reveal your island.


This effect is a far less useful effect, in my opinion, but it’s still worth including. Again it uses the placement and removal of bridge ends to give the appearance of desert sand. If you want to create the effect of a river drying up or meadows becoming arid and bare, simply place and remove bridge ends wherever you want a patch of sand to appear. Done in timed stages, this could gradually show a pond receding, a river drying up or even a sea splitting into two! This is essentially the same as the aforementioned ebbing wave trick, but remember that if you want the created sand to be walkable, you will have to have a walkable terrain there at the start of the game.

I haven’t included pictures to guide you through the other effects; once you get the hang of making bridges everything else is quite a simple alteration of the same effect. If you have any new ideas using this effect be sure to let me know!

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