Structural Design User Guide
SDNF Export/Import : Technical Information : Transfer of Curved Members
Transfer of Curved Members
Exporting a GENSEC with only a straight segment goes out as a Packet 10 element: with just a curve segment it goes out as a Packet 60 element. Compound GENSECs are split on export. Importing curves segments come in as GENSECs: straights, currently, are as SCTNs. If they have the AVEVA E3D™ attributes set, the user can rebuild the GENSEC as described below.
SDNF does not have the same concept of complex curved beams as there is in AVEVA E3D™. Packet 60 arc members are just circular arcs. Therefore for export a complex curved beam in AVEVA E3D™ must be split into its straight and arc segments. These are passed through to SDNF with an annotated :SDNFMARK attribute. If the member is part of a GENSEC the :SDNFMARK value has a suffix of ".S<n>" or ".C<n>" indicating a straight or curved segment. The <n> indicates the segment's sequence position. These suffices allow us to rebuild the complex GENSEC if these values are returned to AVEVA E3D™ from the other system.
If the distance between neighbouring segment end points is outside the tolerance limits, SDNF will attempt to build a new GENSEC starting from the next unused segment. The new GENSEC's :SDNFEMARK or :SDNFMARK attribute will have a suffix .PART<int>, from 2 upwards. No imported members will be lost. In the Compare and Merge process, this new part will appear as an ADDED member while the original part will be indicated as having changed, as it will have a reduced number of points.
However, if the user can restore a GENSEC in AVEVA E3D™ it may well be different from its original as the types of CURVE element are normalised to be THRU based curves.
New straight linear members may be replaced by GENSECs according to the !!sdnfSCTNtoGENSEC flag. Members that are already SCTN elements in the model will not be changed.
Comparing GENSECs is only down to the point count level on the spine. The actual point attributes are not investigated, except for the start and end points. If there are the same numbers of POINSP and CURVE members respectively these are checked. Any alteration to these numbers will indicate changes. They must be inspected visually for comparisons. The re-imported CURVE element are likely to have changed because we only import 1 type - a THRU point, although there are 6 or 7 different types of CURVE points in AVEVA E3D™, each with different attribute combinations.
1974 to current year. AVEVA Solutions Limited and its subsidiaries. All rights reserved.
AVEVA Logo