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wind_lumberyard [2017/09/13 12:57] (current)
titterton created
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 +====== Lumberyard Wind ======
 +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:
 +  - Get the vertex colors correct on the model.
 +  - Select the fan and enable wind.
 +  - Tune the fan parameters to get the desired motion.
 +
 +===== Vertex Colors =====
 +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.
 +
 +==== SpeedTree Controls ====
 +To let SpeedTree set the vertex colors, do the following:
 +  - Enable "​Wind"​ on each Branch generator you want to move independently.
 +  - Edit the "​Wind"​ profile curve to control which parts of the branch bend more.
 +  - Edit the "​Wind"​ profile curve on Leaf and Frond generators to control which parts of the leaf ripple more.
 +
 +Once you've done that and enabled wind your model should look something like the following screen shot with wind enabled.
 +
 +{{ ::​wind_ly_auto.jpg |}}
 +
 +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.
 +
 +==== Custom Vertex Colors ====
 +If you want to control the vertex colors directly, do the following:
 +  - Select the Tree generator and Enable the property "​Compute Flags:​Vertex colors."​
 +  - Edit the vertex color properties of each generator directly.
 +
 +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:
 +
 +  * Red: Fine detail bending for leaves and fronds (1.0 = bend the most, 0.0 = bend the least)
 +  * Green: Timing offset for branch motion (use a different shade of green for a branch and its children to offset branch oscillations)
 +  * Blue: Branch motions amount (1.0 = don't move at all, 0.0 = move the most)
 +
 +===== Wind Properties =====
 +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.
 +
 +===== Exporting =====
 +When you [[export_lumberyard|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.
 +
 +===== Best Practices =====
 +The following list outlines a few things to keep in mind when tuning wind.
 +
 +  * Custom vertex color editing is typically unnecessary.
 +  * SpeedTree mimics Lumberyard'​s algorithm in the editor but it may behave slightly differently in Lumberyard.
 +  * Favor high frequency but small amplitudes for leaves.
 +  * Make sure your "​Strength"​ value matches the magnitude of the wind direction vector in your Lumberyard scene for the best match.
 +  * Making "​Wind"​ profile curves "​Min"​ curves is a quick way to zero out wind effects, especially when using leaf-on-leaf modeling techniques.