- Trim Curve Preference
An IGES file can contain curves defined using real space, parameter space, or both. When you import a part from an IGES file into Abaqus/CAE, the surface and the trim curves are converted into an internal representation of the part. By default, Abaqus/CAE uses the information stored in the IGES file to decide how the trim curve is defined; alternatively, you can force Abaqus/CAE to always use either real space or parameter space.
Always use parametric data. This option computes the trim curve parametrically using the surface on which the curve is lying. Each of the data points on the trim curve is located by a surface parameter (u, v). Abaqus/CAE evaluates the surface corresponding to the data point and generates three-dimensional coordinates for the point.
If the underlying surface has too many sharp deflections that cannot be accurately defined parametrically, the trim curve may not lie on the surface when Abaqus/CAE tries to reconstruct the part. This produces a trimming error and may result in gaps between edges.
Always use 3D data. This option computes the trim curve from the three-dimensional coordinates in space—the part's coordinate system—together with an indication that the trim curve lies on the parametric surface. Each of the data points has its own three-dimensional geometrical point; as a result the trim curve must be re-evaluated each time the surface is moved. The trim curve can move only along the surface. The Always use 3D data option should allow trim curves to stay with their underlying surface; however, this is not guaranteed. If you select the Always use 3D data option, the import will take longer to complete.
- MSBO
A Manifold Solid B-rep Object (MSBO, entity type 186) is an IGES term for a B-rep solid. Like all B-rep solids, the MSBO entity indicates the overall topology of a solid entity by referencing all the trimmed surfaces that define the solid. Abaqus/CAE sets the MSBO option automatically after scanning an IGES-format file and finding the entity.
For an IGES file to contain an MSBO entity, the CAD package that created the file must include the MSBO in the export procedure. CATIA V5 allows for the MSBO entity; SOLIDWORKS does not.
- Levels
CAD applications can store entities in an IGES-format file in a sequence of levels (also referred to as layers). For example, different levels can contain geometry, dimensions, text annotations, construction lines, notes, or a legend. When you import a part from an IGES-format file, Abaqus/CAE scans the file and the Create Part from IGES File dialog box displays a list of the levels that were found in the IGES file.
If a level contains something other than geometry, such as dimensions, Abaqus/CAE ignores the level during the import. However, if a level does contain geometry, you can delete the level from the list in the dialog box and Abaqus/CAE will not import the level. You must import at least one level. As a result, if the IGES file contains only one level, the Level field is not available. Abaqus/CAE ignores any levels that you enter that are not present in the IGES file.
If you encounter problems during the import, you may want to modify the default settings.