Controlled randomized porous structures and methods for making same

A method of creating an orthopedic implant comprising:

• creating a computer-aided design (CAD) model of an implant structure prepared by the steps of:
• populating, via one or more computer processors, a space including a porous CAD volume with a plurality of regularly-spaced seed points;
• perturbing a location of the seed points a random distance in a random direction;
• and
• performing a tessellation of the CAD volume based on the perturbed seed points to divide the CAD volume to a plurality of internal volumes;
• wherein edges of the internal volumes define locations of one of the plurality of struts;
• and
• wherein vertices of the internal structure define locations the nodes where the opposing ends of the struts are located;
• and
• manufacturing the portions of the porous CAD volume on or inside of the boundary.

A method comprising:

• creating a model of a porous structure;
• and
• manufacturing the porous structure in accordance with the model using a computer-aided fabrication apparatus;
• wherein the model of the porous structure is created by a process comprising:
• defining an array of volumes, each volume comprising a plurality of faces, a plurality of edges and an internal volume;
• placing a plurality of seed points at predetermined locations on the plurality of faces, on the plurality of edges and in the internal volume;
• randomly perturbing the locations of the seed points;
• and
• tessellating the volume based on the perturbed seed points to create a plurality of sub-volumes, wherein edges of the sub-volumes define locations and lengths of struts and further wherein the vertices of the sub-volumes define end nodes of the struts;
• wherein the locations of the seed points on the faces of the volumes are perturbed as a group;
• and
• wherein the locations of the seed points on the edges of the volumes are perturbed as a group.

A method comprising:

• creating a model of a porous coating having a volume and a desired shape for placement on a substrate;
• converting the model to a format compatible with a computer-aided apparatus;
• and
• sending the converted model to the computer-aided apparatus for use in manufacturing the porous structure;
• wherein the model is created by:
• joining together a plurality of identically-shaped whole base volumes having randomized internal struts such as to occupy the volume of the desired shape of the porous coating except for remaining portions of the desired shape having a volume less than the volume of a whole base volume;
• defining one or more Boolean intersect volumes for the remaining portions;
• creating one or more partial volumes to fit the Boolean intersect volumes;
• and
• joining the plurality of partial volumes to the plurality of whole base volumes using a Boolean unite function to fill the remaining portions of the desired shape.