Prepare for 3D printing

• watertight
• not too many intersections
• avoid small details (0.8mm minimum detail, but tall objects should be thinker)
• if part snaps together with other part: allow clearance
• if part snaps together with other part: make sure the part can be inserted

• If Cura is slow: set the option “Infill > Skin Edge Support layers” to 0

Use different slicer settings in the volume of a selected object.

Example: use a more dense infill in a specified area

• Add the object you want to print.
• Add the object you want to define the dense infill with (a cube could work just fine).
• Change the size and position of the second object so it overlaps the first object at the desired location.
• Select the second object. In the side bar, go to per model settings and select Modify settings for overlaps.
• select infill mesh only
• select the following settings:
  • Wall line count: 0
  • Top Layers: 0
  • Bottom Layers: 0
  • Infill Density: the desired value for your print

When you're using Gradual Infill Steps in your main model, don't forget to add Gradual Infill Steps: 0 to the per model settings