dynamic model loading

Yes this is possible.

Here an example where I have a list element ("select-1") where I set a list via json object

$scope.populateModelList = function() {
var my_json=[ 
 {
 display: "Ventil_3_sequneces",
 value: "app/resources/Uploaded/Ventil_3_sequneces_publish.pvz"
 },
 {
 display: "Anim Door",
 value: "app/resources/Uploaded/anim_door2.pvz"
 },
 {
 display: "777777",
 value: "app/resources/Uploaded/11406550_CR4_VM_ILL.pvz"
 } ];

$scope.view.wdg['select-1']['list'] =my_json; 
};
 

I am loading the list when the view is entered (event):

$scope.$on('$ionicView.afterEnter', function() {$scope.populateModelList();});

So I could now manually select  the value in the list element -  this action which change the value. I set the binding of the select-1 widget to the model source that when I change the value in the list it will change the source of the model-1

It is possible also to laod and start sequence automaticaly by javascript (example HoloLens):

$scope.app.loadsequence1 = function()
 { $scope.setWidgetProp('model-1', 'sequence', "app/resources/Uploaded/l-Creo 3D - SecondTestFigure.pvi"); 
 twx.app.fn.triggerWidgetService("model-1", 'playAll'); 
 };

 In case that you have a synchronization problems you can use some delay

//this will call the function load sequnece with 1000ms delay
$timeout( function() {
 $scope.app.loadsequence();
 console.warn("app.loadsequence() executed"); 
 $scope.$applyAsync();
 }, 1000); });