How to get exactly 3 shells

[chrisbare]

I'm trying to figure out the right math/settings to get 3 perfect shells in the walls of my model.
My settings:
Nozzle Diameter : 0.4
Extrusion Multiplier: 1.0
Extrusion Width: Manual 0.4
Outline/Perimeter Shells: 3
Primary Layer Height: 0.2

In my model I made the walls exactly 0.4 x 3 = 1.2mm thick

The slicer decides that there is extra room in the middle and does a wiggly middle shell. I'd like to get this to be a perfectly straight shell like the inside and outside.
What am I missing? Is there another setting that affects how wide the lines actually are?
Is there an overlap setting I'm not seeing?

Thanks for any suggestions,
Chris

[brian442]

I think what you're seeing is the gap fill. That's used anytime the gap is an odd size and can't perfectly fit another set of perimeters.

So if you only want perimeters for this part, you could go to the Advanced tab, and set the thin wall behavior to "only use perimeters for thin walls". Then you won't have any gap fill, but you need to make sure the software can fit another set of perimeters. So if the walls are 1.2mm thick, then you could set the extrusion width to 0.3mm, which will allow 2 sets of perimeters to fit (4x0.3mm = 1.2mm)

Otherwise if you have smaller irregular sized gaps, then you probably want to stick with gap fill since that can fill the variable spaces

[NitroXpress]

Yes, unfortunately Simplify cannot create a odd number of perimeters...

[dkightley]

And here we have another great example of where better thin wall behaviour would be the salvation....

viewtopic.php?f=23&t=3471

How many more times am I going to have to highlight this awful deficiency in the software that could so easily be sorted out???????

[Fallen Munk]

You need to use concentric fill.

[3Drasle]

And here we have another great example of where better thin wall behaviour would be the salvation....

viewtopic.php?f=23&t=3471

How many more times am I going to have to highlight this awful deficiency in the software that could so easily be sorted out???????

All the S3D team care about, is adding new printers.