Friday, 17 April 2015

Wind: Off the Map

Here I have added the simple grass wind Node. This is a simple way of adding a constant level of movement to foliage. Although this could have been sufficient it does give some odd results, the grass does kind of bob around unnaturally. This can be slightly improved by adding a mask before the world position offset node and unticking movement on the up and down axis.

I then looked into making a more natural and random wind affect. This was when I was introduced to the following method of creating wind.

There are some unnecessary nodes here but the new method is basically the Lerps and everything left of them. What I have done here is created a Texture Object, in this case in the form of a normal map. This huge object moves on the horizontal Axis’s around the unreal level. The amount and speed that it moves is determined by the Panner Node, the size of the Texture by the Texture Size Node that sits below the Texture Object.  Then you can alter the strength of this wind by multiplying the output before finally plugging it into the material.  

As the Texture Object moves around using this method it changes the world position offset of the material, using the information that the Texture object is casting onto the affected material and its geometries position in the world at that point in time.

…………………………………? I think I may have explained this, assuming I get it myself.

The result of this is foliage that appears to move in a random more blustery fashion.

The unnecessary nodes being used above are attempts at fixing the problems that I uncounted as a result of using this new method. This new method worked fine for the grass, but it was strangely flattening the flowers and they were also sitting dead still. Above I have tried to mask off the flowers. I have also masked off the base of the geometry so that only the tops are affected by the wind. I have then tried to use a simple grass node to give life to the flowers. 

This wasn’t successful. What I eventually had to do was remove the grass from material and have the Flowers and Grass on different Material IDs.

Here is the finale Material for the grass. Here I have also made my own Normal for the Texture Object. Up to this point I had just borrowed a random normal from the content folders in Unreal.

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