Bridge Has Multiple Layers
====
If this setting is enabled, the skin in higher layers above the bridge will also be adjusted. You can then carefully tune the flow rate, speed, density and fan speed of the second and third layer above the bridge.

The first layer that crosses the bridge is by far the most influential in how the bridge is going to look. If there is any sagging in that layer, there will not be anything to hold it up. With the second and third layers, there will be material beneath it that can hold (some of) the weight of the layer on top. Yet still, adjusting the layers on top can still have some positive effects.
* Reducing the density can reduce the weight of the material that will be resting on the lower layer.
* Increasing the fan speed makes the material sag less, putting less weight on the lower layer.
* Reducing the printing speed has a similar effect to increasing the fan speed, as it allows the fans to blow on the material more.
* Reducing the flow can reduce the weight of the material as well as improve the effectiveness of cooling.

However there are other effects too which makes each of these settings a balancing act. Enabling the bridging settings for the second and third layers as well allow tuning more precisely, but also requires more experimenting to get a good result.