What happens is that the volume where the cube intersects with your object is locally sliced with different infill.

Locally, with a rotated 2nd cube, the infill % is raised to 100 %. The picture shows a cube on the buildplate with infill 20 %.All is more or less illustrated in the screenshot below Also with 'per object settings' (now called: 'Per model settings') select the option 'infill density'.It should overlap with the section that you want to change the infill for. Position the cube to overlap part of your model.Select 'Infill Mesh' (now called: 'Modify settings for infill of other models') and enable that setting.Select the cube, and use the button 'per object settings' on the left side.Import a second object (for example a simple cube).Unselect 'keep models apart' (now called: 'Ensure models are kept apart') and 'drop models to build plate' (now called: 'Automatically drop models to the build plate') in Cura preferences.I could not find the video ( on second thoughts, I think it was animated GIF) posted by Team Ultimaker, so I quote a section of one of their forum topics.Ī short how-to: (italic font is not in the reference, but added to reflect recent version of Cura) Note that this is an advanced feature which is not easy to use, but quite handy if you master it. extra stiffness for compression stresses) at the fastener holes. This is extremely useful for lugs and brackets where you need some extra infill (e.g. So basically, you use other models to intersect with your primary model to create intersections that can take a different infill percentage. What you need to do is load your model into Cura, then load other objects (models) at the size of the area/volume you want your infill differently and position those at the position you want a different infill. I've used a feature in Ultimaker Cura that can be used to alter the infill density locally. Firstly the implementation in Ultimaker Cura is described, secondly how you can do this in Slic3r. This answer explains that you can have different infill within the same part.

Adding internal supports simplify 3d