Perimeters not closed at thin walled part

[MvM]

I have a problem with printing an object for a customer.
The problem is described as follows:

The object has a few spots with holes in it where a small bolt will be pused through.
Here, the walls get relatively thin.
The problem is that whatever settings I uses, Simplify3D simply refuses to completely draw a single continuously perimeter but instead skips the part where the wall gets very thin and then will later on just sort of 'fill in' the opening.
This not only makes for an ugly surface at that point but makes the shell weaker also.

I have tried many options: Single perimeters infill, gap fill, single perimeters, overlap%, minimal travel length adjustement etc., but it keeps doing the same thing or even skips the whol infill part and create an opening.
This is wat the preview looks like.

Does anyone know any solution to my issue. The same parts seems to slice without problem in Cura.

[rrdavis]

Because you didn't include any sample files, all I can do is guess, but it looks like that thin wall is smaller than the extrusion width you are using for your perimeters. So the software is correctly changing to the single extrusions to try to print the very thin features. If you tried to print that with a normal perimeter with your current settings, it would be largely over-extruded, since you would end up with a perimeter on either side.

So I would say you have 2 options
1) Use the single extrusions that the software is using now, since they are doing exactly what they are intended to do (great article about those options here btw: https://www.simplify3d.com/support/arti ... -features/)
2) Go to the Extruders tab and change to a manual extrusion width, and set that to a smaller value. For example, if you set it to 0.3mm, you might be able to extrude thinner perimeters which may have a chance at extruding that thin wall. If you are going to go with this approach, you probably want to go to the Advanced tab, and set the external thin wall type to "perimeters only".