The easiest way I've found to make complex climates is to make a small set of distinct 'root' land types, such as grass, beach, cliffs, etc, and then derive a set of 'mixed' land types that blend between these root types. For example, if I have root types of 'grass' and 'cliffs', I can create a mixed land type of 'steep grass' by blending the parameters between these two land types.

The best place to start work is with the most common 'root' land type, which in my Frosty climate is snow:

To add the snow land type I'm going to double-click on the '<< new land type >>' option in the climate editor list. This opens a text entry dialog (for the land type name), and then the land type editor interface:

Conveniently, the 'Colour' for this land type has initialised as {255, 255, 255}, which is white, and therefore highly suitable for a 'snow' land type.

As for setting parameters; this bit is easy. I'm going to double-click on the BaseProb entry and set the following value:

If you've had a squizz at the climate algorithms page, you would know that BaseProb is simply the default 'score' of a land type when generating the attributes map. There is no special reason why I chose a value of 1 - I could just of well have chosen eleven million. However, by keeping the numbers in a fairly sane region, where the land type score is around 1, your make things easier later on when you're tinkering with balancing several or tens of land types. This also means that your climate will play-nice in maps with multiple-climates, as the other default climates included with L3DT (eg 'temperate', 'arctic') are all balanced at around-about 1 also.

I'm going to leave all of the other settings as-is for the moment. We'll come back to them if and when we need to.

Next I'll create a land type called 'Cliffs' and set the following values:

I've set Colour to dark grey, and Grad to 1, which will give this climate a high score for steep land. This was an arbitrary choice, whick I'll improve upon if required.

Now is probably a good time to see what has been achieved. To apply my climate to this map, I'll select the design-map pencil tool, activate the climate option, pick my new 'frosty' climate, and hit 'apply to all':

Thereafter, I will seleect the 'Operations→Attributes Map→Generate map' option to see the coverage of the land types:

As expected, snow is almost everywhere except the steep bits, which are cliffs. However, I'm not terribly pleased by the cliffs coverage; I did want a bit more. What I need to do is improve the cliffs score by increasing either the BaseProb or the GradCoeff parameters. My personal bias is to mess with the BaseProb in preference to the other parameters, so I'll re-open the climate editor and set the following values for my cliffs land type:

Now, after OK-ing my way out of the climate editor, I will use the Calc AM button in the climate manager to re-generate the attributes map:

This is more to my tastes.

I find it does help to visualise the land type coverage by generating the texture map. However, I haven't set any of the textures for these land types, so I'll have to do that now.

For snow:

For cliffs:

These values have been copied from the temperate climate, so I'm cheating a little bit here. Anyhoo, I'll close the climate manager and select the 'Operations→Texture map→Generate map' option.

Yup, it looks like the snow / cliffs coverage is OK. The only problem is that I've got snow underwater…

I'm going to create a 'sand' land type to go underwater. Water-dependent land types are more complex, as you have to set the BaseProb, Water and Salin parameters correctly. I tend to cheat, and copy the values from existing climates, such as the 'beach sand' entry in the temperate climate:

When I re-generate the attributes map using the Calc AM button in the climate manager, I get this:

Looks alright to me. As a texture, it is:

Yup, you can see the slight yellow sandy fringe around the water's edge. The standard sand texture is probably a bit too cheerful for the mood I am trying to create, so I might make this something a bit more greyish later-on when I'm changing the textures.

• 'Mixed' land types »