There are two phases to create stereogram:
1) create a depth bitmap with program rtw
2) create the stereo bitmap from depth bitmap with another program.
1) from file .rt you want to create a stereogram, modify or add the attribute render equal to "depth". Add if you want the attribute depthmax, depthmin, depthback.
depthmax is the max value allowed in the depth image, depthmin is the min. depthback is the value for dot without objects ( the background ).
The default values are: depthmax 64, depthmin 48, depthback 64. Remember that the output is a grey scale image, but in the 24bit format. For some use you must convert it.
2) use you own program to create the stereogram