Isosurface landscape tutorial.

Isosurface landscape tutorial.

Introduction:

This tutorial explains how to create a landscape with isosurfaces. It is assumed that you have already read the MojoWorld manual and learned something about MojoWorld itself. I.e. instead of writing "click on the cloud-like icon" I am going to write "Open the Sky Editor" and so-on :-). It should be even better if you would have read the isosurface session logs.

Tutorial:

Start from a blank planet. Open the Sky Editor and select Volumetrics in the Atmosphere DDLB. Open it.
You'll see a lot of parameters, but don't worry; for now you can simply ignore most of them. These parameters are global for volumetric stuff and act on all isosurface "layers" you'll create. [new version] By the way, to find out what each parameter does, you can use the tooltips (hover the mouse-pointer over the parameter name and the tooltip will appear. You can set the tooltip delay in the preferences). [/new version]

Explanation of some parameters:

Light from above, side and below defines the ambient lighting. It lets you create realistic land.
If things looks sorta too smooth, you can increase Detail (3 is good value).

Tutorial continued:

Open the window big enough and scroll down.
There you will see DDLBs numbered 0, 1, 2, etc [new version]you will see exactly one DDLB but as you choose stuff, new one will appear. So you could create unlimited number of things [/new version].... In the DDLB you need to select Surface. Open it to edit the surface.
There are many parameters, again, most could be ignored for now. [new version]Again, as in Volumetrics, you can use tooltips.[/new version]

Explanation of a few parameters:

Lowest altitude, Highest altitude: The Isosurface is contained between the lowest and highest altitude. Everything outside gets cut out, so isosurface-affected area doesn't extends into infinity.
Shape: There you put your Texture that'll define the shape of the surface. You will have solid in places where the shape is less than 0 and you'll have clean air where it is above. It is somewhat similar to water & ice: in places where the temperature in Celsius is below 0 you get ice and where it is above 0 you get water. Important note: if the camera is located within the surface, you will get some special color in the RTR and in the render. In such case, move the camera around or get above the [i]highest altitude[/i].
Reliability: Sometimes the isosurface doesn't render properly. In such case you may need to increase this value.

Tutorial continued:

Set Lowest altitude to -100000 (we are making landscape and don't want any holes.) Select Shape to be a Texture, and in the "Value Texture Editor [SURFACE:SHAPE]", create a New Texture (if you are lost here you need to read the MojoWorld manual). Create two Texture Leaves. In the first, replace "Monofractal" with "None" and replace "World Position" with "Altitude". Edit the Blend, set Blend Type to "Subtract".

The second Texture Leaf will more or less correspond to the landscape height. You can edit it like you do for mojo terrain, for example set result scale to 200, or edit the Output Control's curve.

Explanation:

Altitude - [second Texture Leaf] (where "-" is subtract) will be bigger than 0 when altitude is higher than value of [second Texture Leaf] and will be smaller than 0 when altitude is lower than value of [second Texture Leaf].
In other words, let [second Texture Leaf] gives out h meters. At altitudes below h meters shape will be equal to [altitude that is lower than h]-h , and it is negative. And at altitudes higher than h you will get [altitude that is higher than h]-h that is positive.
So, [second Texture Leaf] defines the height of the landscape; above the landscape there is clean air (see description of [i]Shape[/i]) and below there is dirt, rocks, etc. In the second Texture Leaf, you just define the land like you normally do in MojoWorld. For example; in the Output Control edit the curve and set Min Input=-1, Max Input=1, Min Output =100 and Max Output=200. You will get landscape that changes approximately between 100 and 200 meters. It works almost the same as normal MojoWorld terrains, except that if you use a big result scale, you will get overhangs with no additional work (and sometimes, flying objects. Flying objects is a feature; isosurfaces just render anything that you specify, and if you specify texture that has flying objects, it will render them).
If you use Surface Position instead of World Position, the resulting isosurface terrain will be completely equivalent to a normal MojoWorld terrain (although then there will be no point to use isosurfaces, heck). That is mostly because in the mojoworld terrain texture, surface position is always equal to world position, but it is not so in the Isosurface's shape.
If you know how to work with Function Graphs, you can do that in a FG (using the Subtract Node; Altitude should go into the left side of Subtract! (otherwise you'll get upside-down land :-)) To make the land more interesting, assign a "Simple Surface Material" in the surface's Material DDLB and edit it.

Some tips: you may want to turn off the MojoWorld's landscape and see the isosurface only. To do that, open the Object List and uncheck the eye to the left of "Planet".