3D EM Preview

Before simulating your design using the EMDS simulator, it is recommended that you validate that your three dimensional design has been properly constructed. This will give you confirmation of your design and also simulation of designs which are not correct. The representation seen in the viewer is the same definition that will be used in EMDS. If the view does not appear to be correct, it is essential that the you correct the design before attempting a simulation.

The key benefits of this visual confirmation are:

Correct Substrate Set Up - The substrate information within ADS is defined using the Substrate menu options. Using these commands, the height of each substrate is defined and the corresponding layers are assigned. The previewer enables you to validate that the proper mappings have been set up and that they are the correct height.

Correct Bondwire and Dielectric Brick Placement - Bondwires, described in the schematic window of ADS, are mapped to the ADS layout and incorporated into the overall EMDS design for simulation. Dielectric bricks are defined as part of the substrate definition. Since these portions of the design are difficult to see in layout, the previewer can be used to validate their location and design.

Setting Up the Viewer on External X Window Displays

On Unix/Linux Systems, it is common practice to use a local machine as a display and do the actual processing on another machine. The display from the original machine is typically mapped back to the local display using the command

export DISPLAY=machine:0.0

The 3D previewer requires the setting of an additional environment variable, HOOPS_PICTURE. This environment variable is set to the same value as the display variable with the addition of X11/ prior to the machine name. Using the above example, the HOOPS_PICTURE variable would be set to

export HOOPS_PICTURE=X11/machine:0.0

Validating Your Geometry Visually

The 3D Previewer is invoked by choosing the EMDS > 3D EM Preview menu option.This command will start the 3D previewer. The Previewer needs to be started each and every time that you want to review your design as it does not remain synchronized with the current ADS layout. It is recommended that you do not keep one instance of the previewer open while an older instance is present. It will not interfere with the data; however, it might be confusing and cause an unnecessary error.

The basic layout of the EMDS previewer can be seen in EMDS Previewer. The previewer contains a dockable widget that controls the display of the individual mask layers, substrates and port boundaries. Upon startup, a dockable widget is docked on the left-hand side of the previewer.

EMDS Previewer

Additional information is also located along the bottom status bar. On the far left side is the current operation mode. For more information on these modes, refer to Navigating in the 3D Environment.

Identifying and Highlighting Individual Objects

Individual objects can be selected and highlighted in two ways:

Picking on the Screen - Objects can be selected graphically using the mouse. If the previewer is in Query mode, an object can be selected by clicking on any line or vertex of the object. Once selected, the object's lines are highlighted, the object is selected in the material and object list and the coordinates of the selection point are displayed in the lower right area of the status bar.

Selection from the Material or Object List - Objects can be selected from either the material or object list box. Once selected, the object's lines become highlighted.

Identifying and Highlighting Materials

The material selection is located in the docking widget. It has the same controls for individual objects as the Object Tab. In addition, each material's visibility and shading can be controlled using check boxes associated with the material itself.

Controlling the Visibility and Translucency of Selected Objects and Materials

Once an object has been selected, its visibility and translucency can be controlled using the Object Information control located at the bottom of the docking widget. This option enables you to control the translucency and visibility of an object.

It is also possible to control the visibility and shading for the substrate and mask layers. Within the Material portion of the docking widget, each material and object has separate toggles for visibility and shading. By setting these controls appropriately, you can control the visibility and shading for all the objects that share this substrate or mask. However, the translucency can only be controlled at the object level.

Navigating in the 3D Environment

The 3D previewer operates in several different modes. The current mode is displayed in the lower left portion of the status bar. Regardless of the mode, the mouse wheel will enable you to zoom in and out of the design at the location of the mouse cursor on the screen.

Zoom Box - You can select a region on the design by selecting a rectangle around the area of interest. Once selected, the previewer will zoom into this area and update the local rotation origin.
Zoom - You can zoom in or out on the design by moving the mouse up or down on the image respectively.
Rotate - The rotation mode is the default start up mode for the previewer. You can rotate the design around its current origin by holding down the main mouse button and moving it around the screen.
Pan - You can move the design around on the screen by holding down the main mouse button and moving it around the screen.
Query - You can query your model using this command. When you click on an object's edge or vertex, the location and object name are displayed in the status bar. In addition, the object is highlighted and the object is automatically selected in the Object and Material tabs in the Docking widget. Visually, a solid dot is placed if the selected location is on a vertex and a hollow dot is placed if the selected location is on an edge.

Measuring Distances in the 3D Previewer

The measure dialog is activated from the Window/Measure command. Once activated, the measure dialog is displayed.

Measurement is done between a reference point and the current query point . The query point is updated after every mouse selection using the query command. The reference point remains fixed until it is explicitly updated using the Move Current Point to Reference.