Slicing a part the have solid areas

Hello,
Is it possible to slice a part to have some areas that are printed solid, and the rest of the model at the chosen infill %?

for example I need to make a square part with some screw holes, and I want the holes to have a solid 5mm ring around them.
[i.imgur.com]

Thanks
ps, I dont want the entire shell to be the same thickness, only the holes.

Edited 1 time(s). Last edit at 03/05/2016 10:07AM by Dman12.

Yes! You use a "modifier". I have done this many times- it works perfectly.

Start with the object and save it as an STL file:


Draw the modifiers and save them as a separate STL file:


Here they are superimposed:



In slic3r, load the box and set infill to 20% or whatever you want, then load the modifiers using the object settings page, and edit the infill density to be 100%. Slic3r will fill the intersection of the first object and the modifiers at 100% and use whatever infill you specified for the rest of the box.

Edited 1 time(s). Last edit at 03/05/2016 10:51AM by the_digital_dentist.

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

This is perfect. Thank you so much