 Saving the CAD Design as a Low-Resolution STL File |
Because STL files describe a series of polygon meshes, they only approximate the high-level CAD design. The resolution used when creating the mesh determines how closely it matches the original. Reducing the size of the triangles (where applicable) increases the resolution of the polygon mesh.
Low resolution is noticeable on non-planar surfaces, which are faceted, rather than smooth – so much so, that you can see this on the display screen. Printing an STL file saved at low resolution may result in a printed model whose surface is rough. If this is inadequate for your needs, increase the resolution before saving the STL file and printing the model.
A mesh resolution of 0.01 to 0.03 millimeters generally produces a goodquality STL file. Reducing mesh resolution below this range does not necessarily mean that model accuracy is improved. As a rule of thumb, designs that have many contours or curved surfaces need a higher resolution than flat, geometric surfaces.
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| Saving a CAD Design with Very Thin Features |
For satisfactory results, it is recommended that the features of a design have a minimum thickness of 0.6 mm. (Although Objet printers are capable of printing thinner features, this requires that the printer is calibrated to factory specifications.) | |
| Saving Non-continuous Designs |
If a model design contains holes or gaps, it is not suitable for 3D printing. You should make it “watertight” before saving it as an STL file. (It is much harder to fix STL files than native CAD files.) | 
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| Saving Designs with Confined Hollows |
If a model design contains confined hollows, there is no way to remove the support material. Design the model so that support material can be removed.This is especially important when printing moveable parts and parts made from clear material. | 
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| Saving Designs with Inadequate Clearances |
To ensure the intended functionality of the design – for example, relativemovement of parts, fine-detail separation, etc.– clearance between parts of a model should be between 0.25–0.3mm. | |