How to convert EUCLID models to VENUS

The following text describes briefly how to export EUCLID models for use with real-time visualization in the VENUS project at CERN.

EUCLID Models which can be translated:

• Solids (VOLUMES)
• Surfaces
• Assemblies

Currently only Solids and Surfaces in the Assemblies are exported from EUCLID. Lines, curves and 2D symbols are ignored.

How to export from EUCLID:

• Retrieve the model from the Database.
• Make sure all models you want to send to VENUS are in the same coordinate system.
• Export using the EUCLID Wavefront interface:
  1. From the EUCLID main menu, go to: APPLICATIONS=>INTERFACES
  2. Select: WAVEFRONT
  3. Depending on the object you want to export, choose: Solid/Surface , Advanced Surface or Assembly
  4. Use the default parameters: DOUBLE POLYGONS: NO TRANSFER : FAST

  EUCLID will then write a set of files with extension .obj in you EUCLID working directory.

  NB! Please liberate the EUCLID Wavefront license after the transfer!

  UTILITIES=>RESOURCES=>DEACTIVATE

How to send the files to the VENUS team:

1. In a terminal window, create a sub-directory for all the Wavefront (.obj) files you have created. As an example, if you have exported models of the ATLAS Experimental Area: mkdir atlas_ea mv *.obj atlas_ea

   Or, if you exported an ASSEMBLY from EUCLID as many objects, do:

   mkdir atlas_ea mv {NAME_of_ASSY} atlas_ea
2. Then you can create a .tar file to simplify the transfer to VENUS: tar cvf atlas_ea.tar atlas_ea compress atlas_ea.tar
3. Transfer the file by ftp to VENUS: ftp venus user: eucvenus pass: *** put atlas_ea.tar.Z bye
4. Then you can delete all the files from your workstation: rm -rf atlas_ea*

Recommended methodology:

The methodology used to prepare the models in EUCLID depends on the target software, EUCLID model and what the model should be used for.

Preperation in EUCLID and conversion procedure on the VENUS side may differ if the model is to be converted to i3D for use with WWW or if it is to be converted to CLOVIS for navigation in Stereo.

General EUCLID modelling rules:

• Always make sure that the topology of solids and surfaces is constistent. Open solids will not be transferred correctly to VENUS, even if the look ok on the screen in EUCLID. Tro to avoid using too many levels in Assemblies, as this leads to problems.
  • If you have problems exporting an ASSEMBLY, try to EXPLODE the Assembly at all levels and re-create the assembly again.
• For fast navigation in real-time, one needs to reduce the number of polygons. Mulitple levels of detail is way to cheat here. It is therefore recommended to create 2 versions of each EUCLID assembly to be exported to VENUS, one simple and one detailed one.
• You can export Assemblies from EUCLID if colours and textures are going to be added by the VENUS team.

Quick session for novices to EUCLID:

First login in to VENUS under the username eucvenus. Then start EUCLID with the command euclid from a Winterm or via the "Applications" root menu.

Select the initialisation table VENUS to get the correct settings for Civil Engineering projects (Unit meters.)

Once in a EUCLID3 session, please follow these steps:

1. First set the external connection from where you want to retrieve EUCLID models: MGMT/EXIT=>DB=>RETREIVE-GRP =>CONNECTION Type in the desired connection, e.g. ATL_EA,SOUT1_EXP_INFRA,AT13
2. Retreive the assembly you want to export from the database: MGMT/EXIT=>DB=>RETREIVE and select object by typing the name or picking from the stack.
3. Follow the steps indicated under "Export from EUCLID" above, and choose ASSEMBLY and Several Wavefront Objects . (This may take some time, as EUCLID has to write one file for each object.)
4. The .obj files from EUCLID will all be written in a directory tree with the name of the top-level assembly. To proceed, follow the steps indicated under "Transfer to VENUS Computers".

Furter conversion on VENUS

You will find a description on how to proceed to create fly-through models on VENUS computers from EUCLID data from the links below. (Venus team & associates only)