Consider the dual extrusion model of a biological membrane (https://onedrive.live.com/redir?resid=3 ... le%2cgcode).
It starts with the skirt alright as it should. But then it swaps tool head. That destroys all advantages of priming the nozzle before an important part of the model. It should print the skirt and then go right to parts of the model to be printed with the same nozzle. Then, it prints the 2nd line ((Skirt/All Extruder setting) of the skirt AFTER the shield. Again it makes no sense, since the beginning of the green line will often not extrude well. These extrusion problems should be in the skirt not in the shield. After that it swaps nozzle again from green to blue to print the actual model. Another mistake. Now, that the green nozzle is primed it should print the green parts of the model on the same layer first before changing to the blue tool head.
It is very important that the 1st layer of the ooze shield is printed after priming the nozzle with a skirt. Especially, if you print directly onto the build plate without a raft, the first millimeters of the ooze shield will often be badly printed. This will cause problems in the subsequent layers. The shield often comes closer to the model and can even stick to it. This is why the 1st shield layer should be printed after priming the nozzle with a skirt.
In summary, the best order in the print code generated by Simplify3D should be:
- skirt blue
- model blue 1st layer
- skirt green
- shield green 1st layer
- model green 1st layer
- shield blue 2nd layer
- model blue 2nd layer..