Three-dimensionally article with knock out support defined with build material

A computer-readable storage medium for manufacturing a three-dimensional article with a sequence of layers, the computer readable storage medium being non-transitory and storing software instructions that in response to execution by a processor cause a three-dimensional printing system to:

• receive a data file defining a hollow three-dimensional article to be formed from a build material;
• analyze the data file to identify an opening that converges to an apex along the sequence of layers, the opening defined by a perimeter edge of the three-dimensional article that extends at least partly in a vertical direction;
• and
• define a support structure attached to the perimeter edge that closes the opening including:
• a structural sheet portion that defines a majority of an area of the support structure except for a boundary contour between the structural sheet portion and the perimeter edge;
• and
• an interface web portion that substantially closes the boundary contour and defines a weakness contour for removing the structural sheet portion;
• and
• operate a print engine to fabricate the three-dimensional article and the support structure.

A three-dimensional printing system for manufacturing a three-dimensional article with a sequence of layers, the three-dimensional printing system including:

• a print engine for fabricating the three-dimensional article;
• and
• a controller for controlling the print engine and including a processor coupled to a non-transitory storage medium, the non-transitory storage medium storing software instructions that, when executed by the processor, perform the following steps:
• receive a data file defining a hollow three-dimensional article to be formed from a build material;
• analyze the data file to identify an opening that converges to an apex along the sequence of layers, the opening defined by a perimeter edge of the three-dimensional article that extends at least partly in a vertical direction;
• and
• define a support structure attached to the perimeter edge that closes the opening including:
• a structural sheet portion that defines a majority of an area of the support structure except for a boundary contour between the structural sheet portion and the perimeter edge;
• and
• an interface web portion that substantially closes the boundary contour and defines a weakness contour for removing the structural sheet portion;
• and
• operate the print engine to fabricate the three-dimensional article.