Oh and by the way, in regards to the original question, here is the "Developer" page from the original Heli-X page: http://www.heli-x.net/developer_e.shtml
It's in german, but here's the google chrome auto-translation of the pertinent info for you:
HELI-X used for photorealistic rendering of panoramic photos in Cubic format.
The idea of this format is as here described.
Each panorama consists of 6 frames. This ideally have a format of 2048 by 2048 pixels.
The six images must all be in a Directory name. The name of the directory is the name of the scene.
The scene Alvier is for example in the directory with the name Alvier. It consists of 6 files with the following names: Alvier_back.jpg, Alvier_front.jpg, Alvier_left.jpg, Alvier_right.jpg, Alvier_bottom.jpg, Alvier_top.jpg.
In addition, the file Alvier.xml is needed. Here are included the direction of the sun's rays to the start position of the helicopter and the amount of information horizon.
Conversion of the equirectangular format to the format Cubic
This requires a program that can convert the equirectangulare image. This can be done, for example, HDR Shop or Pano2QTVR 1.6 or the tools of Eric Gerd's use.
With HDR Shop is obtained as the result of a big picture that needs to be cut or into 6 parts, with Pano2QTVR or the tools of Eric Gerd gets you 6 frames.
Before Umtransformieren and cut it may be necessary to reflect the image yet, because currently the image is used in HELI-X as you would see it from the outside.
If the original image does not contain the full 180 °, it must be increased before the Transfomation yet.
Matlab scripts realize the filling of the output image and the cutting of the Cubic-image, I can provide.
Starting position of the helicopter and the direction of the sun's rays
In the xml file, which is part of every scene, you should specify the start position of the helicopter and the direction of the sun's rays.
The coordinate system in HELI-X is a right-handed system. The x-axis points to the right, the y axis pointing upward, and the z-axis points to the rear.
The starting position of the heli is so specified in the xml file: x, y, z Here, the y value does not matter, as is seen in the positioning of the helicopter, where the ground is. The y-coordinate is automatically selected so that the helicopter is on the ground. That's why you let the y value to zero.
In order to find a suitable starting position, you can enter the-DheliX.statusformat = 1 option in the command line in a batch file or in a shell script. Then, in the status bar in HELI-X of the helicopter, the current position is indicated by its x, y and z coordinates.
The direction of the Sonnenstrahlöen is important for the generation of the shadow. Here one of the x, y and z components of the vector which describes the direction of the sun rays. Since the sun always comes from above, the y value is always negative.