The Renderer


In this chapter the main functionality of the COVISE Renderer is summarized. Like the map editor, one renderer is started on every host in a cooperative working session, once the master renderer has been brought up on the master map editor.

The design of the Renderer supports collaborative working (for more details see chapter 5, COVISE CE - Collaborative Working): Basically the Renderer works in a "what you see is what I see" mode. This is called the Master/Slave Mode or Tight Coupling. It means, that every partner in the session has the same viewpoint in respect to the rendered geometry objects. Only the master has the ability to change the view in the other renderers. On the slave side it is possible to change the camera position independently from the others as long as the master isn't changing anything. As soon as the master performs an interaction, the slaves automatically become synchronized and updated. (Strictly speaking, there is a slight difference between "Master/Slave Mode" and "Tight Coupling": "Master/Slave" causes the slave renderer to be updated at the end of a move only, whereas "Tight" makes a contiuous update. The two possibilities have been introduced due to performance considerations.)

Alternatively, the master has the ability to switch to a second mode called Loose Coupled Mode. When this mode is enabled, every partner has full access to all Renderer functionalities without disturbing the other partners setup and view. This mode is convenient when the partners have stopped their discussion about the current rendered objects and want to do some postprocessing on the data, like changing some colors, adding light sources, saving or printing etc..

The discussion on the data is supported by introducing Telepointers. A telepointer marks a position in the renderer's window to guide the other partners to interesting details on the screen. Each renderer has a telepointer attached to the current mouse position, which is sent to the remote renderers.

In addition, the renderer supports stereo viewing mode with the Crystal Eyes shutter glasses as well as with various autostereoscopic viewing devices. It also supports the Spaceball or the DLR Spacemouse for 6Degree of Freedom interaction.

Getting started

To start the Renderer simply select the module named Renderer in the category Renderer in the MapEditor. After a few moments the renderer's icon [*] is displayed in the MapEditor canvas and the renderer main window appears on the screen as shown in [*].


Note that you can resize the renderer according to your needs, but reducing the window size may hide some of the menu components. By clicking on the module setup button in the Renderer icon, the data object and parameter list for the Renderer appears ([*]).

As you can see, no parameters can be set or adjusted, and there is currently only one input port called DO_Geometry. In the future there may be additional input ports, e.g. for pixel images. Unlike other application modules in the COVISE environment, the renderer has it's own Motif based point and click user interface. You can connect all modules with geometry output ports to the renderer's input port. The renderer will accept any number of input objects. After an execution of a complete module network, the renderer will appear highlighted while new objects from local memory or remote machines are sent into the module. New rendered objects will be shown in the geometry objects list in full name. You can find out your point of view in respect to the scene by looking at the coordinate axes and their orientation. If you cannot see objects just select the View All icon on the right side of the drawing area.

You see the objects as you would look through a camera lens. While pressing the left mouse button and dragging the mouse around in the Viewer Area, you can move the camera around the scene. This allows you to rotate the whole view around a point of interest using a virtual trackball. The viewer area uses the camera's focal distance to figure out the point of rotation, which is usually set to be in the center of the scene. You can also translate the camera in the viewer plane by using the middle mouse button as well as zoom (getting closer or moving backward from the scene center) by using both left and middle mouse buttons. The viewer area also supports seeking (see description of viewer pop-up and decoration). You can also use the decoration thumb wheels around the viewer area for most of these operations. Changing the camera means changing the view in respect to all visible objects. If you want to do editing operations like scaling certain objects or changing some colors, you need to switch to the Edit Mode (or Pick Mode) first. Therefore, press the Pick Mode icon on the right side of the viewer area. The cursor changes to an arrow shape and you can select objects now by clicking on them with the left mouse button. A wireframe bounding box appears around the selected object and the name of the object gets highlighted in the geometry object list. Now it is possible to edit this object by bringing up multiple manipulators and editors, all explained in detail in the next sections. If you want to return in viewing mode click on the View Mode icon. Note that editing operations are only possible in master mode. Only the master has access to the menu bar functionality. For the slave renderers the menu bar is disabled.


Cooperative Working Modes

see Chapter 5, COVISE CE, section MasterCtrl, subsection Synchronization

Using the Telepointer

see Chapter 5, COVISE CE, section MasterCtrl, subsection Telepointer

The Renderer's User Interface

In the following sections the components of the renderer user interface are discussed.


The Viewer Area

In the viewer area objects are displayed and can be manipulated in several ways. The coordinate axes show the current view orientation.

Direct Interaction

Using the mouse buttons in viewing mode affects the camera position, the line of sight, and the angle of vision in respect to the scene. In the default viewing mode, the mouse buttons have the functionality as described earlier. In edit (pick) mode, pressing the left mouse button selects the object under the mouse cursor. When seeking is enabled by clicking on the seek icon, pressing the left mouse button starts seeking to the selected point.


The Viewer Popup Menu

The popup menu ([*]) is activated by clicking the right mouse button while the mouse pointer is positioned in the viewer area. The popup menu contains several items and sub menus. These are:

The Decoration Area

The decoration consists of three thumb wheels for rotating (Rotx, Roty) and zooming (Dolly) as well as a zoom slider trim (Zoom) and six viewer icons to the right side of the viewer area. These icons are shortcuts for some of the viewer pop-up functionality. From top to bottom there are icons for

The Menu Bar

The menu bar of the renderer window is shown below.


File Menu


Viewing menu

The viewing menu is shown in [*].

Editors menu


Manips menu

Manipulators are used for direct manipulation of a certain object, like the editors explained in the last section.


This way of manipulation is more direct than using editors, but less precise than using the sliders. To attach a manipulator to an object, switch to the picking mode and select a manipulator type in the Manips Menu shown in [*].

Now click on the desired object. The manipulator appears and surrounds the object. There are different manipulators to transform, rotate, scale, and move an object in the viewer.

Lights menu

The lights menu is for creating, editing, and removing light sources in an object scene. This is a feature used for changing the appearance of an object by changing its illumination. Light information is currently not sent to other renderers in a cooperative working environment. Each entry in the menu is explained now in detail.


Sync menu


see Chapter 5, COVISE CE, section MasterCtrl, subsection Synchronization


Pressing Help provides you online help for the Renderer - but you can easily branch e.g. to help for MapEditor or Modules.

The Information Area


On the left side of the information area, the list of currently displayed geometry objects is shown (together with the colormaps used).


If you click on a certain object in the render area the name of the object gets highlighted in the object list. It is also possible to select an object in the render area by clicking on it's name in the object list. The red bounding box appears around the selected object in the render area to highlight the selection. Thus, similar objects can be distinguished by their unique name.

On the right side of the information area there are four lines; the first two display the collaboration status of the renderer:

Using Spaceball and Spacemouse

If the Spaceball or the DLR Spacemouse is connected to your workstation, you are able to manipulate the geometry objects in 3D space in a six degrees of freedom fashion. The device should beep two times at renderer startup time when initialization of the device was successful. To move an object around select the object in picking mode. The device is now attached to the selected object. Some of the device buttons provide some additional functionality:

If no object is selected, the spacemouse changes the viewpoint in respect to the scene by changing the current camera position.

Stereo Viewing Mode

image29.png Some platforms support stereo in a window viewing. Stereo viewing is enabled by choosing Stereo Viewing in the renderer's preference sheet. You return to the default mode by deselecting Stereo Viewing in the preference sheet or typing in a shell window:

/usr/gfx/setmon -n 72HZ or /usr/gfx/setmon -n 60HZ depending on the type of monitor attached.

Head Tracking Mode

currently not implemented

Martin Aumueller 2016-03-23