Q: How can a seemingly empty array create user normals ???
A: It’s not empty. It’s so full it cannot display the string 🙂 I pasted in a string of 7558 characters that was a comma-separated list of the user normal vectors created by Modify > Component > Set User Normals > Polygon.
The “gotcha” is that String to Array appears empty when you paste in large strings.
n = Application.Dictionary.GetObject( "sphere.polymsh.ICETree.StringToArray" ) #print n.Parameters( "Value_string" ).Value print len(n.Parameters( "Value_string" ).Value) # 7558
eX-SI 
So you’re saying there is no arbitrary limit to storage of ICE strings then? Or just that the limit for visualizing them in a textbox is smaller than the actual true limit?
I’m just saying that if you paste in a “long” string, the String to Array PPG cannot display it. I don’t know what the actual limit is…in this case I’m going to guess it is a PPG control limit.