I am designing a part with a material which can bear up to a certain stress.
To keep the stress within the design limits, I need to ensure a certain surface of solid material per layer, in other words a minimum amount of extruded filament per layer and a smoothly changing infill ratio so that the infill can transmit the load efficiently to the neighbouring layers.
The part has an irregular shape and I cannot simply increase the infill ratio for the whole object because the part is big and it would cost more time and filament. I also cannot build straight pillars of solid material inside the part because there are no regions which are suitable for a continuous pillar.
How can I calculate and apply a smoothly changing infill ratio or in general how to ensure that each layer is made of at least a certain amount of material?
I use Prusa Slicer for slicing and Fusion 360 for the design.
Related questions about variable infill, which however don't answer my question because I need to specify the amount of material and because I need a smoothly changing infill ratio: