Help: Trying to print models on top each other

[DomXDOTMulita 0]

I'm trying to print models on top each other. I'm using per model settings to add an invisible barrier in order for the model to print "in the air" when in reality it will be supported underneath, however a part is not working properly. Of the 4 different models to be printed on top of the baseplate, only one is performing properly. The first of the four is a pair of racquets. These are printed with duel extrusion and the g-code performs very well. The layer view looks perfect. When I went to follow the same process for the 2nd of the four models, a ball (flat circle), the layer view shows no extruded layers, but the scrolls on the side show that there are multiple layers. When I tested this print, it printed just fine. The same happened when I tried to print the date on the ball. The final model, the last names, are shown to be 1.4 mm on the z-axis, just like all the other models. However, instead of slicing to show no layers, or be raised 1.4 mm on the z-axis, the part drops to the baseplate. In layer view, I only see the print with 3 layers above 1.4 mm. I have the settings for auto drop to baseplate turned off. I have checked all of my per model settings and it is equal to all the other models. I am not sure why this is no longer working. 

 

To be specific with my per model settings. The baseplate is set to normal, wall thickness:0, wall count:0, infill % and infill density:0, top and bottom thickness:0 (all subsets of top and bottom:0), top and bottom layers: 0 (all subsets of top and bottom layers is also 0). The models to be printed on top are also normal per model settings.