Hello, this is my first post in this forum and I want to share an easy tecnique that I am using for generating a Boolean Mask for bounce-back domains.
The boolean mask is described in the documentation: Bounce-back domain from boolean mask
First of all you need a picture of your domain:
http://img6.imageshack.us/img6/3462/geometria.png
The image should be rotated 90 degrees clockwise in respect to the desired final geometry.
The white region is the allowed region to the fluid, the black region is the forbidden one.
I created mine with Inkscape[/url], so it is a [url=http://en.wikipedia.org/wiki/Scalable_Vector_Graphics]SVG vectorial image that can be resized without a loos of quality.
Then using the “convert” tool from the ImageMagick suite[/url] you shall convert the image to the [url=http://en.wikipedia.org/wiki/Netpbm_format]Netpbm format:
convert geometry.svg -compress none geometry.pbm
The “-compress none” option is the trick of this how-to.
Now you shall delete the first two lines of the pbm file and you are done.
I wrote a really simple bash script to generate the dat file:
#! /bin/bash
convert "$1" -compress none "$1"".pbm"
lines="`wc "$1"".pbm" | awk '{ print $1 }'`"
let 'lines = lines - 2'
tail -n $lines "$1"".pbm" > geometry.dat
This is an example of the result:
http://img715.imageshack.us/img715/1021/finalot.png