I have not enougth know how in Visionaire.
But because I want to use the same effect later I search for a solutuion
I have not found to set the rendering methode for objects and sprites.
Helpfull will be multiplication, or add.
I found a hint in a 2 years old forum post.
You can do with partice. But dont write how.
Partikel have a rendermode: addhttp://wiki.visionaire2d.net/index.php?title=Particle_Rendering
Maybe make a emitter with no speed, very long lifetime and move it around by lua-script?
Rendermode for object or sprite will be nice