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Solid file format such as “.stp“ and “.iges“ contain surface representations of the model. Although these types of models contain an extremely precise and compact description of the model, they are not suitable for 3D printing. In this case the platform automatically takes care of converting surface representations of the model into meshes, and then proceed proceeds with the mesh optimization.
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Mesh optimization has the ultimate goal of assuring that your file is printable and that the outcome will have has the best possible quality. The platform will attempt a first optimization to make sure your model meets the minimal requirements for printability, and then operate a second optimization to improve the surface quality of the final printout.
Minimal requirements for printability
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The first optimization step makes sure that the minimal requirements for printability are met |
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Printers of several manufacturers will reject the 3D model if the following requirements are not met:
Manifoldness or Watertightness:
Manifold meshes are characterized by strong connectivity. In simple words, each triangle of a mesh should be connected to exactly 3 neighbor triangles.
Strong connectivity guarantees that none of the following problems occurs:Holes
Extra Rendundant triangles
Merged objects
Correct triangle orientation:
Meshes with correct triangle orientation uniquely define the inside and the outside of the object. If this requirement is not met, printers may not be able to correctly distinguish between printing volume and empty space. Triangles with incorrect triangle orientation (in black) may also not be visualized correctly by CAD programs.
Requirements for best surface quality:
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The second optimization step attempts to improve surface quality by removing self-intersections. |
Absence of intersections:
For a high quality printout, the volume of each object needs to be uniquely defined, but self intersecting objects may define the same volume multiple times .
Although many printers accept files with self intersections, the surface quality of the final printout may be heavily affected.