initial position of vrml scene when run new simulation

% extract model name
model_name = bdroot(gcs);     
% Here we assume that you have the VR Sink block under its original name in 
% the model
% get the handle to the virtual world associated with the VR Sink  
wh = vrworld(get_param([model_name '/VR Sink'], 'WorldFileName'));
% save the current status of the virtual world to the file associated 
% with the  VR Sink
save(wh, get(wh,'FileName'));

Of course, in order to preserve the initial status of your scene, you should backup your original VRML file and arrange copying it to your working scene, when you want to start the simulation with initial status.