Exercise manager. How to create a new object type from a CAD file

What can be created New object models can be created from CAD files containing vehicle geometry to be used later as only inactive (target) ships, submarines, aircrafts etc. Currently, only STL (stereolithograpy) files are supported. Lots of them can be found on the Internet, look for example, at 3D Content Central Google 3D Warehouse The latter contains lots of 3D models in SKP format and there is a free tool for model creation and change - Google Sketchup. The SKP models can be converted into STLs by installing a free plugin for the Sketchup which can also be found on the Internet. Succession of steps The generated files must be copied to all networked computers, so, in case of networked simulators, ALL NETWORKED slave computers must be on and connected to network at the time of creation. The first thing we need is a CAD file which describes geometry of the new object. At the moment only STL (stereolithographic) file format is supported. It can be either binary or ASCII. Such files contain minimum information to describe geometry/topology of the object, namely only set of triangles with normals. No information about colours, textures etc. is contained in the file. So, we first start the process of creation of the new object by going into "Objects/Create new object type" menu of the exercise manager. The dialog requires some basic information about the new object, namely
  • object type (ship, airplane or whatever)
  • STL file location (file should not be very large, reasonable size is up to 5M)
  • main colour to paint the object (suggest gray to warships etc.)
  • approximate length (it will be recalculated by the program)
  • After you click [OK], the following happens:
  • the specified geometry file is copied into the installation/Visuals directory
  • the STL file is converted into its binary represenation used in the simulator, a .tpatch file (may take some time)
  • these two files are copied to all networked computers, they all must be on and connected!
  • The next step is a usual procedure of creation of active vehicle or target for this model by using "Objects"/"New target (inactive object)" or "Objects"/"New active object". On selection of the new object type from the list It is much easier to use newly created object as targets than as an active vehicle, as an active object requres specification of viewer position, windows in superstructure etc. Firstly, we consider some basic modifications of the model to make it applicable for the simulator. The first correction is coordinate axes orientation. The simulator uses its models with axis X pointing forward, Y - to the left side (when looking forward) and Z - upwards. The origin should be approximately at the centroid, but Z = 0 must be at
  • waterline level for ships and
  • at land level for aircraft and cars
  • The axes orientation can be changed here by rotating the model using the "rotate around" buttons. All sizes should be in metres, so use the "Scale" button for this purpose. The axes can be moved by dragging them to a new position. As a result, the final picture should look like for ships or for airplanes. From now on, the new object can be equipped with lights etc. as usual, using the corresponding sheets of "Properties". This object will produce standard wakes on water surface, issue standard sounds when passing by, follow routes i.e. behave like a usual target. However, it is not enough for an active vehicle, for which such important things as windows in superstructure (to look throught) and viewer position should be specified. At the moment they are not specified interactively, but can be specified in a specification .vehicle file appeared in the installation directory which contains all information about the new vehicle.