[Andy]

If I understand what you are saying correctly, it's not a bug or fault. For transparency to work correctly, transparent surfaces need to be drawn last. If tranparency is to be done totally correctly, the transparent parts must be drawn in depth order and pixel by pixel, like you'd get in a ray-tracer.

AC3D doesn't sort the surfaces for transparency and even this wouldn't be enough for it to transparency to properly.

the artifacts you are seeing are probably just different ways that the graphics libraries handle drawing transparency and are nothing to worry about.

If you need a fully rendered image with transparency, you'll need to render the image with Povray or similar.

The solution in AC3D for windscreens, windows etc is to put the transparent surfaces in an object and put it at the bottom of the hierarchy so it is drawn last. This way you'll get the best preview image.