User Guide

Startup Panel

When starting up the Vizard software a panel is presented where the user can select which simulation to visualize. To play back a previously recorded BSK simulation press the Select button and navigate to the binary BSK recording file. After a file has been selected press the Start Visualization button.


To live stream data from a running Basilisk simulation to Vizard make sure that the connection type is DirectComm and the mode is Live Streaming. When starting a Basilisk script that uses live streaming (see scenarioBasicOrbitStream with liveStream set to true) the socket address, which is tcp://localhost:5556 by default, is shown in the terminal window. Copy this and paste it into the Vizard socket address text field. Finally press the Start Visualization button to begin the visualization.

The default Vizard communication can be overwritten using the following variables:

viz = vizInterface.VizInterface()
viz.comProtocol     = "tcp"
viz.comAddress      = ""
viz.comPortNumber   = "1234"

This example would cause Basilisk to use the socket address tcp:// to connect to Vizard.

Vizard Communication Parameters








Transport protocol to use for the connection. See all protocol options here.




Network address to use for the connection. This can be either a host name or an IP address.




Port number to use for the connection.

View Modes

To engage with the visualization, the view point can be rotated and the user can zoom in and out. There are three view modes available:

  • Spacecraft-Centric View Mode (default): Here the spacecraft is drawn 1:1 while showing other celestial objects about it. When rotating the center of the spacecraft is the center of rotation. The spacecraft trajectory is not shown in this view. You can zoom in and out locally, but if you zoom out too far then the view mode switched to a planet-centric view mode.

  • Planet-Centric View Mode: Here a planet-wide view is presented. When rotating the view point this is about with the center of the planet as the center of rotation. The spacecraft trajectory is shown. The spacecraft is drawn at an exaggerated size so it is visible as a 3D object in this view. To return to a spacecraft-centric view mode double click on the spacecraft. If you zoom out far enough then the mode switches to a heliocentric view.

  • Heliocentric View Mode: Here a solar system wide view is shown. The planets are drawn enlarged to make them visible, and the planet trajectories are shown as well. If the spacecraft is orbiting a planet it is not visible in this view. If the spacecraft is on a heliocentric trajectory it is shown, also enlarged, in this view. Double clicking on a planet returns the user to a planet-centric view.

Space Vehicle States

The following sections describe the basic user interface elements of Vizard. Some settings can be set via a Basilisk script as described in the BSK Scripting Settings.

Basic Position and Orientation

Vizard is able to show the position and orientation of the spacecraft being simulated. If one or more planets are being modeled, then the spacecraft is show relative to the nearest planet.

Reaction Wheel States

If Reaction Wheels or RWs are modeled, then a RW panel can be opened from within the Actuator menu bar item. Here the RW wheel speeds and motor torques are shown.


Thruster States

If thrusters are being simulated then a range of visualizations can be enables within the Actuator menu item. The options include to open a Thruster Panel which shows the thruster firings as bar charts. The thruster HUD uses a particle engine to illustrate if a thruster is firing. Here the length and density of the particles is related to the strength and duty cycle of the thruster. The thruster geometry option draws small cones where the thrusters are modeled to be. This is useful when debugging that a thruster configuration is being properly modeled. Finally, the thruster normals option illustrates the thrust axes being modeled.


File Menu Item

Settings Panel

This panel provides access to some system defaults:

  • ambient brightness

  • keyboard controlled camera angular rate

  • keyboard controlled camera zoom rate

Save Messages To File

Allows all the protobuffer message, or a sub-set, to be saved off to a file. This document is located inside a sub-folder VizardData inside the user’s home directory.

View Menu Item

The View menu tab contains a range of Vizard options. A range of coordinate frames can be toggled on or off.


Edit Pointing Vector

This allows a line to be drawn from the spacecraft aimed at another celestial body such as the sun, a planet, etc. The spacecraft location is referred to as “Inertial”. The purpose of these lines is to have a quick visual reference in what direction another body is located. The lines can be hidden or removed as needed. Some celestial bodies come with default colors such as yellow for sun heading, or red for Mars heading, etc. However, each line color can be customized as needed.


Edit Keep Out/In Cone

This feature allows for a cone to be added relative to the spacecraft which indicates if a cone about a particular body-fixed axis intersects with a celestial object. For example, this can be used to add a cone to validate that the sensor axis doesn’t get too close to the sun (keep out cone), or if the solar panel normal axis stays within some cone to the sun (keep in cone). If the cone in/out condition is not triggered, then the cone is opaque. If the in/out condition is triggered, then the cone becomes solid.


Edit Location

Here you can control what ground or satellite locations are shown, as well as toggle if the location boresight vector should be shown, or/and the location coverage cone. These locations can also be scripted in python. However, this panel allows for locations to be added or edited on the fly.

Display VizMessage Log

This opens up a panel which displays all the raw protobuffer message states. You can downselect what type of messages to how with toggles on the left side. The messages are updated in realtime as the simulation progresses. Note, if a message is sent only once on start-up, it is only shown on the first simulation frame. This panel is useful when debugging protobuffer communication features.

Adjust GUI Scale

This brings up a panel where a global GUI scale factor can be set. This is useful increase or decrease, the Vizard font, panel and GUI element sizes. The Vizard default values switch automatically with the screen resolution. If a specific value is set in this panel than this over-rides the auto-setting.

Model Inventory Panel

If you want to see to the Vizard space object model inventory panel, then select View/Model Inventory as illustrated in the following image:


Hot-Key Directory

The key h will open up a help panel showing all the hot-keys that are available. This includes a camera-centric flashlight model with L, or ways to engage constant camera rates, or stopping all camera rates with s, etc.



This allows you to turn on labels for spacecraft, planets, even actuators such as thrusters etc.


Model Inventory

Brings up a panel to edit and modify the 3D CAD models that are used by a spacecraft or a planet.


Time Menu Item

The Time menu tab contains a range of Vizard time or mission date related option. Some of these items have a keyboard short-cut assigned.

  • Playback in Real time: This mode syncs up the playback speed to be real time where 1s of simulation time takes 1s of real time. This can be increased or decreased as desired.

  • Playback at Frame: This mode plays back each data frame as it arrives. Thus, the visualization is playing back a data file as fast as it can without skipping any data frames. If you press the Plus icon then the data playback speed is doubled to 2 by only showing every second frame. Pressing Plus again doubles once more the data rate to 4 to showing only every 4th data frame. If you press negative the trend is reversed. You can slow down the playback as well in this mode in that a data rate of 1/2 means a data frame is held for 2 unit cycles.

  • Use 24 Hour Clock: This toggles between a 12 hour clock using am and pm and a 24 hour clock.

  • Show Mission/Sim Time: This toggles the time bar to show either the simulation elapsed time or the mission date and time. Note that if the Basilisk simulation doesn’t set an epoch date than January 1st, 2019, 00:00am is assumed by the simulation.

  • Show Data Rate: This toggle shows the data frame rate. If this is 1, then every data rate is being shown. If the rate is 2, then only every 2nd data frame is shown. A data rate of 1/2 means a frame is held for one rendering cycle to slow down the simulation.

  • Show FPS: This toggles on the frames-per-second on the lower right of the screen

Camera Menu Item

The Camera menu item allows for custom camera views to be created into the visualization. The first item called Changed Main Camera Target brings up a list of simulation objects that can be made the focus of the simulation camera window. This makes it easy to switch between an Earth-centric and a spacecraft centric simulation point of view.

Note that the Camera menu list contains 2 default camera options that can be turned on. Selecting either camera 1 or camera 2 will open a stand-alone camera view as shown below. Finally, if more camera views are required, these can be added with the Add Camera menu option. Within a camera panel the user can select from which object the camera is simulated, and where this camera is pointing. Below the camera is selected to point camera along a body fixed vector.


In this second illustration the camera is chosen to point toward another simulation object such as the Earth. Here the user can select to point the camera at the target (nadir), along the velocity direction (along-track) or orbit-normal,.


If you press the snap shot icon on the lower right of the camera panel, then the camera view is captured and stored as a PNG image within the user’s home directory.

Import a Custom Shape Model

When Vizard starts up it represents the spacecraft using a default CAD model called bsk-Sat. The following section illustrates how this default spacecraft model can be replaced with with a custom CAD model in an .obj file format, or by using a built-in shape primitive.


Vizard starts up showing a default spacecraft shape. To select a different shape, a custom CAD model can be imported using the OBJ file format. Go to the File menu and select Import OBJ Model:


Next, select the OBJ file that is to be imported into Vizard.


The next panel allows the CAD model import to be customized. The user can modify the origin offset, the CAD orientation and the CAD scaling. The latter is useful to convert the CAD model into meters used by Vizard. The model center and model extrema information is provided as a convenient. A bounding box can also be draw as a convenient to make sure this is correctly configured. Note that if a model is to be applied for each simulation instance, then see how createCustomModel() can be configured to script this OBJ import process as illustrated in BSK Scripting Settings.


At this point a panel appears that allows you select the object for which you want to apply a new shape, and what shape you want to apply. When ready, press Apply Models to Selected Objects to apply the custom space object shape. Note that instead of an OBJ file a custom shape can also be selected such as a sphere, cylinder or cube.


Built-In CAD Models of Celestial Bodies

While custom CAD shapes can be imported to display celestial bodies and spacecraft shapes, Vizard has several built-in models that are automatically applied if the body has the corresponding name. For the gravitational bodies, Module: vizInterface uses by default the string planetName in the GravBodyData() structure as the gravity body label. If the optional string displayName is set, this this gravity body label over-rides the planetName string. This is handy in that sometimes the gravity body might have an unintuitive Spice ID or name, and the user wishes to label the planet with a more common name such as earth, mars, etc. Further, or override the auto-shape selection and specify a specific shape, use the modelDictionaryKey string to specify CAD model to be used. This allows the CAD keyword and the planet label to be different.

This gravity body label is used in Vizard to select a default shape. For example, Vizard seeks for the label earth (regardless of capitalization) and will find it in earth, earth_planet_data, etc. The following table is the list of built-in Vizard celestial bodies.

Build-In Vizard Celestial Body Shapes

Vizard Keyword





atmospheric shader


atmospheric shader



atmospheric shader

Phobos, Deimos







Advanced Options

File/Compress Messages Option

This option will compress the number of stored vizMessages from the current run. This feature is especially useful during multi-day live streaming simulation runs when the number of saved Module: vizInterface can grow too large for the app to continue running.

Selecting this option brings up a settings panel that allows the user to specify how many messages should be retained. For example, if the user opts to retain 1/2 stored messages, Vizard will delete every other message in the Module: vizInterface dictionary, reducing the Vizard memory footprint.


Compression can be applied when running the Vizard from a Module: vizInterface archive file or when live streaming. Please note that the compression cannot be reversed, but that the archive file, if in use, will not be changed.

Sprite Representation of Space Objects

Vizard is setup to show an attitude dependent 3D rendering of a spacecraft model by default. In a planet centric or helio-centric view the spacecraft is enlarged such that the orientation can still be determined. This is the default behavior if a single satellite is shown. However, if multiple satellites are shown then seeing enlarged 3D renderings can both be a large computation hit and confusing to the viewer. Thus, if 2 or more spacecraft are shown, and the view point is planet- or sun-centric, then Vizard defaults to showing the spacecraft locations as 2D sprites.

The default shape is a white circle. Using View/Sprite Settings opens a control panel to custumize the use of sprites. Different shape primitives and colors can be selected for some or all the spacecraft and planets. Further, toggles are provided to over-ride the default behavior and switch between a 3D rendering or 2D sprite representation.