Geomorph - Getting Started

Geomorph - Getting Started

Starting
The menu bar
The window controlling the creation of a new document
The toolbox
Organizing your Geomorph - Povray work
A few advices before the end of this section

Starting

If the installation worked fine, you should have a Geomorph icon

on your desktop.

If it's not the case, you can start the program by typing geomorph in a console, or under KDE, by typing geomorph in the Atl-F2 dialog.

This is the layout of the Geomorph desktop:

Menus and buttons bar (create, open, close, and the like)

Window containing control parameters during the creation of a new document
/
Window containing the toolbox or the height field pen options

Document windows stack

You navigate through documents with the KDE or Gnome taskbar.

When you start Geomorph, only the menu bar is displayed at the top left corner.

The menu bar

To start, click "Create a new document"

. You'll get a control window on the left side and a document window in the center.
Among the other buttons that you'll use often, I emphasize "save"

(strongly recommended!), "undo"

and "redo"

.

You can read the description of each button by moving the mouse cursor over it a few seconds.

Menus under File / Edit / Tools / ? activate the same functions as the buttons do.

The creation window

The creation window is "modal", meaning that you can't click anywhere else when it is active, even in the document window. This way, the creation parameters cannot interfere with the other open documents.

Icons

and

launch Povray for testing the current height field. The first icon asks for the *.pov scene to use. The second one uses the default scene or the last chosen.

Click "OK" and the toolbox dialog replaces the creation dialog.

The default is a "uniform" height field

of a neutral gray shade. It can be used as a canvas for drawing with the height field pen (

), or as a starting point for adding noise or some kind of warping.

"Uniform" height field

over which are drawn
"hills" (in the background) and a"depression" (in the foreground)

Try subdivisions

and

if you want classical terrains. Click repeatedly on the "Refresh" button to change the pseudo-random seed and you'll see a succession of distinct height fields generated with the same global parameters. The FAQ explains the differences between both subdivisions. Subdivision 2 provides a frequency control (actually a wave length control specified in pixels).

"Subdivision 1" height field

"Subdivision 2" height field

The progressive sum of surfaces

works by adding repeatedly simple surfaces (primitives) of different sizes (or wave lengths). Usually, the primitive surfaces are gaussian bells, but any height field already open in Geomorph can be used as a building block.

Hitting the seed "Refresh" button generates an image with a new structure, as it does with subdivisions 1 and 2.

The huge "Activate" button must be clicked after any parameter change other than the random seed.

"Progressive sum of surfaces" height field

This height field is build with surfaces of all available wave lengths in power of 2 sizes (256, 128, 64, 32, 16, 8, 4, 2 for a 256x256 terrain), displaced randomly.

The following height fields show how we can superimpose two wave lengths (here 64 and 32 pixels) and move them randomly on the XZ ground for starting a terrain.

"Progressive sum of surfaces" height field

- with one wave length of 64 pixels (terrain 256x256)
- XZ displacement and H displacement set to 0
- density set to 60

"Progressive sum of surfaces" height field

- wave lengths 64 + 32 (terrain 256x256)
- XZ displacement set to 50
- density set to 60

The "Shape filter"

makes an "island" from your height field. The same function is available in the toolbox, so you can wait to apply it.

Using the "Shape filter"

with a "Subdivision 2" height field

The toolbox

The toolbox is displayed with brightness / contrast

as the default tool, from the "Filters and other transformations"

block.

Subdialogs depending on a tool or a pen are displayed in the same window, unlike Gimp subdialogs, which are displayed in a new window.

A tooltip is generally displayed for each tool icon if you let the mouse cursor over it a few seconds. See the tools index for more details.

The window bottom contains control buttons, allowing to accept the last results or to reset the document to its previous state.

The current modification is automatically accepted when swapping between documents, tools or between the "Filter and transform" mode

and the "Draw" mode

.

You can always undo the last accepted change by clicking

in the menu bar.

Organizing your Geomorp - Povray work

When installing Geomorph, predefined Povray scene scripts are copied in your /home/.../geomorph/ directory, which you can modify to fit your requirements if you are familiar enough with Povray.

Heavily using Geomorph with Povray would rapidly fill this directory up with tens of documents. Creating one directory for each project can avoid this problem:

/home/.../geomorph/project1/...

A project directory should contain:

(1) The multiple versions of your height field.

(2) Copies of the Povray scripts that you modified, if you chose to do so.

(3) "Secondary" height fields, like the "water maps" and the background terrains used in some Povray scripts. Because these secondary height fields have fixed names, for instance hf_water.png for a water map, regardless of the main terrain, they should be created in separated directories for distinct main height fields. The table of predefined Povray scripts shows the related secondary height fields, when it's the case.

(4) The pictures rendered by Povray, whose name is composed with a prefix, usually _, followed by the name of the main height field.

Notice that there were inconsistencies in the way Geomorph versions prior to 0.40 were managing directories.

A few advices before the end of this section

Save your documents frequently!
In the toolbox window, some options display subdialogs overflowing the desktop. Sometimes, you won't even see the control buttons ("Accept", "Reset", and the like). Use the "hide dialog" / "show dialog" buttons for masking the unused subdialogs.
If you want to debug a Povray scene executed from Geomorph, start Geomorph in a console, so that you can read the Povray messages.

Last revision January the 27th, 2007

Contact: Patrice St-Gelais

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