unwanted geometry with every import

[Oueslati 0]

With every single stl import I get this geometry that takes up quite some space on the build plate.
Every post I could find about this was about turning adhesion but its not that.
It seems to be some sort of fault in the cura import settings but I feel like I have exhousted flicking every setting in cura but the problems persist.
Any ideas? Thanks. (Ultimaker 3)

[Slashee_the_Cow 480]

Those are "disallowed areas" from the printer's definition file. They usually represent areas which models can't sit on but there is room for the print head to move around in that area so you can put stuff right up against it.

 

If it was a hard wall and not a disallowed area, it would limit your buildable area because that would need to take into account having enough room around the edges for the print head to move.

[Dustin 175]

its also not accurate that they are in the way.. the specifications of the machine's max build volume accounts for those zones.. 
the print head cant reach them.

[Oueslati 0]

Thank you Cow and thank you Dustin,
 

8 hours ago, Dustin said:

its also not accurate that they are in the way.. the specifications of the machine's max build volume accounts for those zones.. 
the print head cant reach them.

By saying "It's not accurate that way they are in" do you mean that its reserving more space then it needs to?
Sometimes I want to print as big as the printer and now I cant just center selected but tweak scale and position back and forth the whole time to fit something slightly to the left on the x axis, this feels really unoptimised and inefficient, is there a way to auto fit it in available space?

[gr5 2,265]

I wrote you a long answer and then realized that this article is much better:

https://support.ultimaker.com/s/article/1667337565436

 

Cura does position objects in the center of the printable area by default.  You can click on the object, select the move tool on the left and make sure that "x" offset is zero - that's the center.  The origin is the left side so the center is not zero but the offset is zero.