TOTAL WAR WIKI

Low Frequency Map

09 April 2015

09:24

 

Low Frequency Map

The low frequency map is a height map image file used to create the large scale shapes across all of the tiles on the battle map. It is created using a combination of Photoshop, World Machine and Terry. There are a number of additional processes that need to be carried out on the map to ensure playability for certain battle types.

 

Blocking Out Features

Before you begin work on the low frequency map you need to create a base to work from. This will give you a flat base from which you can work in additional height using Photoshop\Terry.

1. In Photoshop, create an image at 4x the resolution of the ‘tile_map.png’,
2. Fill the background with black (0,0,0),
3. Import a copy of the tile_map as a new layer and scale to fit the image,
4. Select the land portion and fill will a dark grey value ((893,893,893) for example),
5. Save a PSD version of the file
6. Turn off the tile map layer and save a copy of the file as ‘lf_heights.tif’ in the battle map folder (16-bit greyscale),

Running Terry

1. Run the launcher,
2. Select the correct branch,
3. Run Terry (release) build,
4. Select File > Open,
5. Go to raw_data\terrain\battles\[your battle name]\,
6. Select and open the .terry file (if this doesn’t exist see section regarding setting up a new battle folder).

Load Options

Terry can be launched with a number of different load options. They are as follows:

1. Scene (Entities) – this will load the map with catchment visualisation enabled. This should only be enabled when you wish to generate the battle catchments or debug a catchment issue,
2. Editable Low Frequency – due to the size of the low frequency map, this option is available for when you wish to carry out actions that don’t involve height map painting. Note you have to have this selected before you can edit and save the low frequency map!
3. Tile Window Enabled – the tile window is designed so you can open a section of the tile map to work on. Again due to the size of the low frequency file, you will find that when it is loaded there is not enough visual fidelity to accurately paint height. By selecting a smaller section of the map you will increase the map fidelity and allow for more accurate detail painting.

1. 1. Tile Window Centre – this represents the centre pixel from which the window will be loaded. This will match the pixel values found in the tile map in Photoshop,
   2. Tile Window Size – This represents the amount of the tile map that will be loaded in pixels. For most of the painting processes anything above 256 pixels will result in a reduction in visual fidelity when painting.

It is worth noting that even with the tile window selected you may see some clipping\artefacts that will not be present in game.

Blocking Out Details

Terry has the same height painting brushes that are available in TEd. These can be selected using the terrain icon.

Note that in Terry you will see a lower resolution representation of the tiles, without any of the rigid models (trees\buildings) visible. You can now block out height yourself, or you can take the campaign map art block out and combine it with your data to save time. It is worth noting that at this stage the game doesn’t take into account any height represented in the low frequency. This means that units will path find across the terrain regardless of the steepness, and the AI will have no knowledge of any terrain advantages you may be creating. So whatever methods you use to paint the map, bear in mind you are responsible for ensuring playability.

Bedding in Sea Coast Tiles

The coastal landing, or combined land\naval battle, requires all of the beach tiles to be at a specific height. Doing so will ensure all of the beach landing hints are at the correct height in world space. Using an absolute brush in Terry you will want to set the height to 1.88144. You can now paint this height along the sand\water edge until it has been flattened. You can use variable height along the back edge of the tile, as long as it remains plausible. You will need to complete this process for all of the beaches in the tile map. This is a lengthy and quite tedious task, but it is worth doing properly the first time as any inaccuracies will come out in testing, leaving a lot more clean-up work down the line.

Bedding in Port Settlement Tiles

The port settlements also require completely flat low frequency under them to ensure playability. Using an absolute brush in Terry you will want to set the height to 0.141909. You will want to paint this height underneath all of the major and minor port settlements. You will need to pay extra attention to the blend along the edges of these tiles. If it is too flat you will get sea clipping through the terrain. By smoothing and perhaps adding a small amount of height along the back edge you can resolve these issues. You can go slightly into the edge of the tile when smoothing, but make sure you’re not going far enough to start affecting the buildings\walls on the tile.

Bedding in Land Settlement Tiles

The land settlement tiles also require completely flat low frequency under them to ensure playability. As each of the settlements can be at a different height you will need to select and average out the height on a case by case basis. This needs to be completed for both the major and minor settlements.

Bedding in River Tiles

The river pass is a twofold process. Firstly, you must ensure that the rivers are all flowing downhill from source to mouth. You will also want to make sure that the rivers don’t have too much camber underneath them. Secondly, you need to ensure the river crossings with bridges have completely flat low frequency underneath them. The river fords have some slope in the terrain, but if it is too extreme it will break the gameplay\visuals. The river mouths themselves also require a bit of manual clean up to ensure the river spline is terminating in line with the sea plane. There are rock models that cover this area designed to cover up this blend, so there is a small margin of flexibility.

Bedding in Lake Tiles

Any lake tiles will need to have the low frequency flattened around them to ensure the water plane doesn’t clip through the terrain. It is worth noting that the water plane may not match the masked outline of the lake tile and you may need to flatten a larger area of terrain around the tile to achieve the correct end result.

Low Frequency Clean-up Pass

If you have completed the above tasks, you should now have a fully functioning battle map. You will now want to carry out an art pass on certain aspects to bring them up to scratch. This includes:

• Roads – adding interest and ensuring there not too steep\at an extreme camber,
• Mountains – adding interest and height variants underneath the mountainous areas,
• Cliffs – adding height variants underneath the cliff tiles. The assets are designed in such a way that allows them to be pulled out from the sea a certain amount. You need to be careful to keep the low frequency smooth and not paint too much extreme heights as you will get tearing in the terrain along the edge of the tile,
• Popular locations – spend extra time on battlefields that you feel will be on the main drag of the gameplay. Anything near and around settlements is likely to fall into this category.