Subject: Re: Ripples
From: Allen D Hastings <[email-masked]>
To: [email-masked]
Date: Mon, 8 Aug 1994 03:18:34 -0700

>Maybe Allen can provide some insight on the inner workings of the Ripples 
>bump map; I've tried everything I could think of to try and separate out the 
>individual effects of the various parameters, with little success. 
>Specifically, what does the Texture Size parameter define for Ripples, and 
>how is it related to the Wavelength and Amplitude parameters ? In addition, 
>how are multiple wave sources placed (it seems they are all centered at the 
>same spot). Is this placement affected by other parameters ? If so, how ? 
>I'm trying to setup a scene which simulates the ripples in a swimming pool 
>resulting from multiple wave sources interfering, and I've gotten some 
>excellent results by a combination of accident and some rules of thumb from 
>the manual and other users, but I'm not sure why those settings work. Thanks 
>for the help. 

The texture sizes define the dimensions of the ellipsoid containing the
wave sources.  The center of the ellipsoid is defined by the texture center.
The wave sources are randomly distributed within the ellipsoid (unless you
have only one, in which case it's at the center).  As always, the texture
size and center parameters are measured in distance units (usually thought
of as meters).  Wavelength is also in units, and wave speed is in units per
frame.  Amplitude controls how strongly the surface normals are perturbed.
I had hoped this would all be in the manual...
 
- AH