I’ve created and imported a custom 3D model for one of my footprint to add to a currently existing PCB.
I’ve selected this footprint for some parts under CvPcb. The custom 3D model can be seen in CvPcb 3D viewer.
I’ve then re-generated the netlist.
In PcbNew, I’ve re-loaded my netlist with “Exchange footprint” settings to “Change”.
But when I open the 3D view of my PCB, the custom 3D part does not appears.
I guess you already know that the footprint is cached in the pcb file.
To get changes from the footprint library into the pcb you would need to update the footprint. This is done with the change footprint tool (in kicad 5 called update from library)
This tool is found in the footprint properties dialog (shortcut e or rightclick menu -> properties) of the footprint you want to update.
But it could be that this tool does not update the footprint if kicad thinks there are no changes between the cached footprint and the footprint in the library. (I am not sure if changing the 3d model reference alone is enough to tell kicad that the footprint is different. If the update tool does not work, maybe temperately add a line on the fab layer.)