This site renders 3d images from user selected images such as 3d books, 3d cd covers etc, I can find that site is created in php, but couldnt understand what they might be using at server end.
To my observation I find these might be possible methods
1 - They create models using 3d rendering softwares such as blender3d and some how they created a API to replace the layer and render the image from terminal.
2 - They might have used terminal interface of gimp, that they use to replace a single layer with transformation to render the image .
3 - Used any 3d libraries like ImageMagick or gd library to create unque flows for each model using user submitted images (But this is quite alot of process for each model !)
Please suggest me your ideas.