Alias CATIA V4 DirectConnect is a stand-alone utility that allows the exchange of 3D model data between Alias and CATIA V4 using the CATIA V4/Alias neutral format CAI.
Use the following summarized list of modeling practices discussed in this section as a quick reference guide if problems arise.
(CATIA tolerances are set for large scale objects as well as for normal scale objects.)
since this function creates multiknots in Alias geometry.
between trimmed surface boundaries, since excessive amounts of data are created in the resulting surface. If Skin is used
between trim boundaries, check the resulting surfaces for multiknots before export.
and Surfaces > Swept Surfaces > Rail Surface
to ensure and control curvature continuity between surfaces.
Before transferring geometry between Alias and CATIA, consider the purpose of the transfer to plan an appropriate workflow. Two common workflows are:
There are many variations on these two examples. Whatever the transfer scenario, carefully plan the transfer process, to ensure that the appropriate data is written out and is useful.
What happens when you replace Alias geometry
A common workflow using Alias and CATIA together is one where you replace existing Alias geometry in a CATIA model file with updated Alias geometry. This workflow allows you to continue working in Alias, modifying a model that has already been passed over to CATIA.
When you want to update the CATIA database with the completed changes, the surfaces that have been modified are passed to CATIA. You import the new Alias geometry and then redefine the skin that includes the faces in question using the Limit2 > Skin > Create/Modify tool.
If you want to change a face or surface using Alias and then include that modified surface in the CATIA model, you only have to redefine the skin to its members. That is, this time you leave out the original face and include the new Alias-modified face. This way Alias geometry can be used to modify CATIA models at any point throughout the development cycle.
What are the curve to fit distance tolerances in Alias
The Curve Fit Distance is the tolerance to which trim boundaries are rebuilt to (or approximated). The default positional tolerance in CATIA is 0.1 mm, and the AliasCurve Fit Distance setting should be set to 0.01 mm.
This Curve Fit Distance setting should normally be accurate. If you find that it is not resulting in Alias geometry that can be successfully used in CATIA, then experiment with the Curve Fit Distance—it can set to as low as 0.005 mm. This setting enhances the success of post transfer processes, such as skinning, that are to be carried out once the geometry is in CATIA.
Do not set the Curve Fit Distance tolerance in Alias at less than 0.001 mm. Lower than this will affect processing time.
Whether you are creating a model, verifying a model, or debugging a translation, there are a number of tools in Alias you can use to check the quality of the geometry you have created. The most useful tool is the Locators > Deviation Min/max measurement tools. Use this tool to check the maximum distance between any two surface boundaries.