ANSYS is a commercially available finite element program.  Dr. Ohanehi created finite element models of the Daedalus Project shelter.  These models were loaded under simulated loading conditions to determine the panel deflection.  One of the output formats available in ANSYS is a data file containing the cartesian coordinates of the displaced element nodes.  Another file identifies the nodes that make up each of the elements in the model.  This data was combined into one VRML file that is viewable on a web navigator equipped with the proper plug-in (Cosmo Player).  The following PV-WAVE program was used to convert the data files to VRML:

PV WAVE Program

Formating the Data Files

In order to the PV WAVE program to read the ANSYS data files they first needed to be formatted.  All lines of text and blank lines were removed.  The conversion program reads in a set of node coordinates and assigns a sequential node number to the set.  The ANSYS data files did not assign sequential numbers to all the nodes in the range.  This was a crucial point because if there is a break in the numbering of nodes, the conversion program does not account for it.  For this reason, false data was inserted into the ANSYS data file so that the node numbers created by the conversion program corresponded to the ANSYS node numbers.  Once the files were formatted, the conversion program was run and an output file was generated.  This file was then viewed with the IV View program on the SGI workstation.

Conversion Problems

Unfortunately there are some errors in the conversion.  The polygonal data does not seem to be connecting the nodes correctly.  Figure 2 on the previous page shows the ANSYS file that I tried to convert.  This finite element model shows the effects of snow loading on the shelter.  The colors generated in ANSYS are not part of the conversion because we wished to make the CAVE model simulate an actual shelter.  In Figures 3 and 4 we can see that the polygons are not connected properly.  When we remove the polygons, as in Figure 5, we see that the nodal information is correct.

Figure 3:  Converted ANSYS File - View 1

Figure 4: Converted ANSYS File - View 2

Figure 5:  Converted ANSYS File - Nodes

I have not found a way to read the polygonal data correctly.  The computer model conversion did not turn out as I had hoped.  Some work still needs to be done to correct the polygonal data.  This conversion tool could be very valuable to researchers doing work with finite element analysis.  The graphs and images generated by current FEA programs provide extremely valuable information, but the information could be more useful if it can be viewed in a three dimensional environment.  To make the conversion program run correctly, the method by which the polygonal data is read in will have to be examined further.  The program is not reading the correct node numbers from the ANSYS file, and as a result the nodes are not being connected properly.  Ideally, once the node numbers are assigned correctly, users will be able to run the VRML in the CAVE to visualize the shelter in full scale.