Defining a use case

A use case is a group of anchor and load surfaces.

A use case should be thought of as how the part will be constrained and loaded for a given real-world scenario. Anchor surfaces are where the part is constrained from moving and load surfaces are where loads are applied to the part. 

Defining anchor surfaces

The anchor surface selection tool is shown below. Important features are:

  • To add another anchor surface, click the "Add" button. 
  • To remove an anchor surface, click the delete icon ("") next to the anchor.
  • Type is currently set to Fixed. This means the surface is fixed and is not allowed to move in any direction.
  • There are 3 Selection options. The left-most is for flat surfaces, the middle is for concave surfaces, and the right-most is for convex surfaces. 

surface_anchor

Defining load surfaces

The load surface selection tool is shown below. Important features are:

  • To add another load surface, click the "Add" button. 
  • To remove a load surface, click the delete icon ("") next to the load.
  • Type is currently set to Push / Pull. This means the load is either pushing or pulling on the surface. 
  • There are 3 Selection options. The left-most is for flat surfaces, the middle is for concave surfaces, and the right-most is for convex surfaces. 
  • There are 3 Direction options: Perpendicular (normal) to the surface, parallel to the surface, and the option to switch the direction of the load. 
  • The load Magnitude has units of Newtons (N). Enter a specific magnitude or adjust the magnitude using the slider.
  • A load arrow manipulator wheel appears for certain combinations of selection settings. To use the wheel, click and hold anywhere on the perimeter of the wheel and drag your mouse to orient the arrow.

Defining a load is simple. Just select a surface, define a load magnitude, and adjust the arrow so that it points in the intended direction. 

 surface_load

An example of a load definition is shown below. The half-cylinder region of the lever is selected with Selection = Concave and Direction = Normal. The load magnitude = 200 N and the load arrow manipulator wheel has been adjusted so that the load arrow is orientated in the intended direction. Given these settings, the 200 N load will be evenly distributed across the surface in the direction of the arrow. 

surface_selection-1

Notes:

  • A minimum of 1 anchor surface and 1 load surface must be defined to have a valid use case.
  • Cura uses STL files and as such, the Smart Slice surface selection tools have been designed to work with this file type. However, there are limitations inherent in STL files that make selecting certain types of surfaces challenging. This means that you may encounter scenarios where the surface selection tool is unable to select the surface you intended. We are always working to improve our selection tool and welcome your feedback