GrassGenerator 2
user's manual

1. Installation

Copy the plugin and its key file wherever you need (for instance into LightWave plugins directory).
Start Modeler. Use Modeler->Plugins->Add Plugins or Edit Plugins (Alt+F11) and select grass.p file. You will be told that 1plug-in have been successfully added. You will find this plugin in Construct->Additional menu.

Keep your key file in a save place. Updates will not work without it. Free future updates will be available in download section at www.polas.net

2. Usage

GrassGenerator allow you to create various types of grass on a surface of any object.
- draw any shape in modeler to give a grass some place to grow. For best results use quad and triangle polygons only.
- run the plugin fom additional menu.
- open LightWave numeric panel to gain access to GrassGenerator controls ('n' from keyboard).
- play with settings and observe grass deformation in real time in modeler's viewports and in preview area of GrassGenerator interface.
- when you are satisfied with grass shape hit 'Make Grass' to get complete geometry.

3. Interface
All GrassGenerator controls was placed into LightWave 'numeric' panel. You need to open it (hit 'n') and resize to see all controls. It cannot be done from the plugin. Most of users used to have numeric panel open all the time on the right side of modeler and they will not like authomatic resizing and positioning.
At the top of the user interface there is a common part. Beneath it the user interface is divided into two sections: Basic and Advanced.
Common:

Presets - this button will open/close modeler presets shelf window. You can store grass settings there.
Add preset - store grass settings for later usage. Thumbnail will help you to easy find it.

Make Grass - this button creates grass geometry. If you are creating many grass blades it may took a while. This is why it isn't done in real time. In most cases there will be generated more grass blades than you see in a preview (you can specify how much grass blades you want to see in real time preview).


Preview panel - here you can see influence of settings on your grass blade. On the left side you see how much a blade is bended and limits of bend random changes. On the right side you see a blade shape.

Preview grasses - this setting affect modeler's viewports. You can set here how many grass blades you will see in real time preview.

Basic:

Shape type - specify here a cross section type of your grass blade. There are 6 predefined types:
Standard: M - section is created from 5 points, similar to a letter M. This was the only type in previous version of GrassGenerator.
Med Resolution: U - section is created from 4 points, similar to a letter U.
Med Resolution: W - section is created from 5 points, similar to a letter W.
Med Resolution: V - section is created from 4 points, similar to a letter V. Center point is doubled to get a hard edge on a smooth surface of a grass blade.
Low Resolution: V - section is created from 3 points, similar to a letter V.
Low Resolution: - - section is created from 2 points, similar to a minus sign.

Grasses - how many grass blades plugin should create.
Segments - how many segments should each grass blade be built.

Length,
Width - size of a grass blade.

Size variations - limits of random changes of size.

Shape - you can smooth change a shape of a blade, from thick (small value) to thin and sharp (big value).

Crook - maximal angle random blade dissortions.

Grow power,
Bend,

Curling - this settings influence on blade bend.

Random seed - when set not to 0 user is able to repeat random behavior it means that it is fixed random. When set to 0 plugin will generate itself this value and you will get similar grass fields but with different blades arrangement.

Advanced:

Size depends on polygon area - you can select it if you want to get longer grass blades on bigger polygons.

Closed - this option is only enabled when there is user cross section in a background layer. You can specify if it should be take closed (like O letter) or open (like U letter).

Bend variations,
Curling variations
- random limits of bend and curling settings.

Limit polygon angle - this setting allow you to cut off polygons (from an object on which grass should grow) that are sloped too much. 180 means that all polygons will be used. On the examples below this setting was send to 180 and 90.

Distribution power - values 0.8 to 1 forces similar distances between grass blades - it may be called: even distribution. Values < 0.8 allow to vary those distances.

Iterations - Number of tries in getting proper position of item. Value 1 is equal to use very small 'distribution power'.

Density Map - You can use weight map to control grass density. On places where weight map value is +100% will pe plenty of grass blades and where its value is -100% there will be hardly no blades.

4. Miscellaneous

Modelling - object on which you creating grass should have no non-planar polygons. For the best results use quads and triangles only. Nurbs patches are not supported.

Custom blade cross section - you can create your own cross section for grass blade. To use it put it in a background layer before starting the plugin. Predefined types setting will be disabled then. Also Width setting will be disabled and Closed setting will be enabled for you. Remeber that custom cross section will be computed from the origin of the axes, so will get strange results if you put your shape somewhere in 3D space far from the origin of the axes. Your shape should be created in the XZ plane. Y coordinates will be passed over.

Selection - if you make selection on an object before starting the GrassGenerator plugin, grass will be created only on selected polygons.

5. Contact

If you have any questions, comments, suggestions, problems, etc. feel free to contact me:

e-mail: olo@polas.net
ICQ: 81081247
IRC (ircnet): channel #idreams