• David Thompson's avatar
    Add some new model-entity types. · 087c3b5d
    David Thompson authored
    The one needed for the polygon branch is the preview entity,
    which is used to hold tessellation information for visual feedback
    during a geometric operation.
    + Preview entities may be related to model and/or mesh entities;
    + they may have text notes attached to them to be shown on mouse-hover
      or in a list that is tied to rendering (so that brushing the list
      highlights the preview geometry and vice-versa);
    + they may be associated with attributes, but there is not a use case for this yet;
    + they may have properties associated with them indicating that one
      of several preview entities should be selected to disambiguate an