Why do some designs require fixing before they can be made?

When you upload a design to our gallery, you may find that some geometric issues prevent it from being built without modifications. The most common reason is that the design does not unambiguously represent a solid object. Another possibility is that some parts are too thin to be synthesized.

Many 3D software modelling tools currently available focus on creating models for rendering and animation. Most of the time, this type of software does not require the object to be solid and only represents its surface. This information is sometimes insufficient to reconstruct a solid object solely based on the 3D design.
If possible, our software tools will attempt to automatically fix the design. However, some issues require manual editing by the designer. A quick overview of potential issues you may encounter is presented below, along with tips on how to correct them.

  • Borders and holes

    A design may contain surfaces with borders, that do not enclose a volume. These surfaces have no thickness and therefore cannot be constructed. Sometimes, small holes prevent the surfaces from being 'watertight'.
    This issue may be fixed either by simply removing the problematic surfaces, by extruding them (via the "push/pull" or "displace" tool of your 3D modelling software), or by filling the gaps.
  • Incorrect orientation

    In most 3D modelling applications, surfaces are oriented to have a "heads" side and a "tails" side. When the surface is closed, this orientation is used to define the inside and outside of the enclosed volume. Sometimes, the entire surface is not oriented consistently, and does not clearly separate the inside from the outside of the object.
    Most of the time, this issue is fixed by flipping the problematic facets. However, some surfaces cannot be oriented consistently (such as the Moebius strip or the Klein bottle). To build these kinds of objects, their surface must be cut open and thickened via extrusion.
  • Singular points or edges

    When designing a 3D model, some operations may produce ambiguous surfaces that connect to each other on a single shared point or edge. These singularities mean you cannot determine which volumes are enclosed by those surfaces.
    This issue may be fixed by duplicating the singular points or edges until the surfaces are disconnected from each other. The duplicated points or edges may reside in the same location, but each surface must have its own copy.