SpeedTree leverages Lumberyard's native wind mechanism for the Lumberyard compatible versions of the Modeler. Lumberyard wind is based on a combination of vertex colors on the model and a few parameters to control the amount and frequency of motion.
The procedure for editing wind is as follows:
There are two ways to set vertex colors for wind in the Lumberyard versions of the SpeedTree Modeler. You can use traditional SpeedTree Wind controls and let SpeedTree set the colors, or you can control them specifically. The latter is typically only necessary for special case models or unusual wind effects.
To let SpeedTree set the vertex colors, do the following:
Once you've done that and enabled wind your model should look something like the following screen shot with wind enabled.
The generators with “W” on them indicate generators that have “Wind” enabled on them. The vertex colors are displayed by changing the render mode to “Vertex Colors→Colors.” Similarly you can choose to see red, green, and blue independently.
If you want to control the vertex colors directly, do the following:
You have the option of setting the color directly or setting colors relative to the color they inherit from their parents. Be careful though, it is possible to create vertex colors that cause the model to separate or otherwise behave erratically using this method.
A description of how Lumberyard interprets vertex colors can be found here http://docs.aws.amazon.com/lumberyard/latest/userguide/vegetation-bending-detail-intro.html.
Here's a quick reference:
Select the Fan object to reveal the wind properties. Wind direction is a non-normalized vector in Lumberyard; however, in SpeedTree the direction is set by the fan gizmo and the strength value is one of the properties. The direction and strength are for preview purposes only, they are not imported into Lumberyard.
The properties in the Lumberyard group match the bending properties in Lumberyard exactly. Edit these properties to tune the amplitudes and frequencies of the wind motion.
Note: The “Bending” value defaults to zero in Lumberyard. You will see no wind on your model in Lumberyard until you enter a value for “Bending” in the “Paint Objects” section of the Vegetation RollupBar.
When you export the tree for Lumberyard, all of these settings except “Bending” will be imported. There is no mechanism for importing the main bending value via .cgf file, so you'll need to enter your “Bending” value manually in Lumberyard.
The following list outlines a few things to keep in mind when tuning wind.