Does it work if you load the models in a simple script that does not connect to the Vive?
Code:
import viz
viz.go()
object1 = viz.addChild('object1.osgb')
object2 = viz.addChild('object2.osgb')
.
.
.
object15 = viz.addChild('object15.osgb')
How much memory do the 15 objects take up altogether?