When Cranes Fly

One of the little-known modules in Autodesk® Navisworks is Animator. What is Animator?  Animator is that friendly tool that allows you to create a scene with model objects.  The scenes in Animator can be complex or simple.  For instance, a scene can be as simple as having a crane rotate or as complex as having cars moving in a parking lot with a camera following an avatar into a revolving door.  Regardless of the complexity, Animator is there to help you design a scene that brings your imagination to life.

Interpolation is your Friend

The Animator module works by using keyframes.  Keyframes capture the animation set, a group of objects in the animation scene, at a given point and interpolate the steps necessary to connect to the following keyframe.  For instance, if a car moves from point A, the first keyframe, to point B, the second keyframe, Animator will fill in all the missing frames to connect points. 

Figure 1: Interpolation

To make an animation scene, open Animator from the Home tab of the ribbon and click the Animator icon.  In the Animator window, right-click in the left pane and select add animation scene.  Then in the selection tree or the model scene, select the model components you wish to animate.  Right-click the animation scene and select add animation set. 

You can add many animation sets to one animation.  For instance, you might add multiple cars to the same scene to animate a cross street or to demonstrate the ingress/egress of a parking lot.

Animator Tools

The Animator module has many different tools.  The first group of tools includes translate, rotate, and scale.  These Animator tools act exactly as the item tools do, but they do not affect the model objects; they affect the animation set objects’ keyframe settings.  Put plainly, the animation tools will only help change the settings for an Animator keyframe, whereas item tools change the settings in the model scene.  A good practice is to never open the Item Tools tab in Navisworks while working with Animator because you might use the item tool instead of the Animator tool.

To create a simple animation such as a car moving down the street, select the car animation set in an animation scene, and create a keyframe by clicking the keyframe animation tool.  Drag the time slider on the timeline to the point in time where you want the car to be located next.  Click the translate Animator tool and move the car to the desired location, and capture the new keyframe.  Click the play button on the Animator window to watch the car move from point A to point B in time.

The rotate Animator tool is a little more tricky than the translate tool.  In order to harness the true power of this tool it is paramount that you understand the location of the pivot point of the object you wish to rotate.  Going back to the car example, you would need to set a point on the car between the front two tires in order to properly simulate the rotation of the car.  The problem with the rotation tool default pivot point is that Navisworks uses calculation in order to determine the default center of a group of objects.  Since a car is made up of multiple parts, chassis, tires, headlights, etc., and some of the component or layers used to make up the car have floating objects, the center of the object might be 10 feet away from the car.  This means that in order to properly simulate the turning of a car, you will need to adjust the pivot point of the gizmo to the center tires of the car in keyframe A and capture the keyframe with the proper center in keyframe B.  Only by having both the start and end keyframes with the same pivot point location will the car properly rotate.

Figure 2: Pivot Points

To simulate a true rotation of a car you will have to alternate between the translate and rotate tools.  You do not have to capture a keyframe every time you switch tools.  You only have to capture keyframes at critical points.  These points might include the starting spot of the car, the starting spot of a turn, the middle of the turn, the end of the turn, then the end of a street.

Figure 3: Complex animation

Another powerful tool, though commonly forgotten, is the scale tool.  This amazing tool allows you to simulate growth/reduction patterns in the x,y,z planes independently of one another for an animation set.  This means you could simulate the growth of plants over time.  You would simply select the plants you wish to grow/reduce, add them as an animation set to the animation scene and use the scale tool to show the change from keyframe to keyframe.  Another example of using this tool could be showing the hauling away of demolished material from a jobsite to better show owners how LEED standards are being followed.

Animating for Attention

Besides animating changes to geometry locations, Animator can be used to help draw attention to special details during a virtual demonstration of the project.  Animator allows you to tell your construction story by utilizing color overrides, transparency overrides, camera sets, and section sets.
Color overrides and transparency overrides do not interpolate from keyframe to keyframe; however, they are paramount in showing the story of your project.  The color override can highlight any object at a specific time in your animation simulation by drawing attention and detail to that object at the precise time you need it.  When a predefined time has passed, it will return to its original color and another object can be highlighted.

The transparency tool is similar to the Animator color tool.  The transparency tool can make objects semi-transparent exactly when you need to show object behind objects.  For instance, when you are walking through the finished virtual project you may wish to talk about overhead MEP systems.  In the animation scene, you could set the ceiling to go transparent at the exact time you start talking about the overhead MEP systems.

Figure 4: Animated transparency

The camera set is a key piece of an animation scene.  This set allows you to guide the animation to pre-defined locations.  You can create a camera set from an existing saved viewpoint animation, or you can create specific camera points with keyframes.  Either way, Navisworks interpolates the frames between keyframes to simulate a perfect, smooth walkthrough.  You can only have one camera set per scene.

The section set is another feature that is useful to call attention to key features of a project.  The section set allows you to create section planes or section boxes and animate their behavior.  For example, you could create a section set that uses a section box to cut through a project while a camera set follows the section box, and both pause as key elements are highlighted from the color keyframes.  When multiple features of Animator are connected together, a full animation story can be created.

Figure 5: Section Set and Coloration of a School

Animating the 4th Dimension

Besides being used to tell a story about key parts of a building, Animator also allows you to add animation sequences to a 4d simulation.  For instance, if you wish to animate construction equipment during the grading portion of the project schedule, you would simply use the translate and rotate tools on the grading equipment and save them as an animation set.  You would then select the animation in the Timeliner window. 

There are three animation options: Scale, Match Start, and Match end.  Scale will adjust the animation to match the start and stop points of the schedule.  This is very useful because you might create an animation that is 15 seconds long, but has to cover three months of time in the construction schedule.  By using scale, the 15 seconds will be scaled to fit the three-month schedule duration during the 4d simulation playback. 

The other two animation settings are match start and match end.  Match start begins the animation as soon as the scheduled item starts and ends exactly as the animation is set to end, which may be long before the scheduled item’s duration ends.  This means if the animation lasts five seconds, Timeliner will start the animation as soon as the scheduled item starts, but the animation will stop after five seconds as it will be complete.  Match end simply makes the animation stop at the end of the scheduled item and starts the animation just in time to ensure the end animation matches the end of the schedule item’s duration.

An example of how this is useful is to create a crane boom swing in Animator and setting it to ping pong, which means as soon as it hits the end of the animation it will reverse and do the animation backwards.  When combined with loop, the crane can continue simulated operation throughout the duration of the project when attached to a crane activity and set to scale.

Figure 6: Animations in Timeliner

An added benefit to animating the Timeliner sequence is that it can be integrated into clash detection.  Remember, you can clash items in time.  This becomes critical for some jobs such as medical facilities.  For instance, think of a large piece of machinery such as an MRI machine. In the 4d simulation an activity would be scheduled for it to be lifted into place.  Animator will allow the machine to actually be lifted through its proper routing with the proper construction equipment while other objects are moving in at the same time.  This allows all of these animated objects to be clashed in time.

Animator Limitations and Fixes

Unfortunately, Animator does have some drawbacks.  The biggest problem is Animator’s inability to select multiple keyframes and move them all at the same time.  You are forced to move each individual keyframe if you wish to change the animation’s duration.  Fortunately, if you are creating the animation for the sake of a 4d simulation, you can just rely on the scale setting to properly extend or shrink the length of your animation. 

Another problem with Animator is the tendency to use the item tools instead of the Animator tools.  This is a problem because the item tools are in such a familiar location for Navisworks users that they tend to be used instead of the Animator tools.  For this reason, it is highly recommended that you do not even open the Item Tools tab when working with Animator.

Animator is not Autodesk® 3ds Max, but it does allow you to make useful walkthroughs that can tell an important story.  You can export animations to keyframe pictures or to an avi file.

To sum it up, the animator module is an often forgotten tool in Navisworks.  It allows you to tell a story and have the model assist you in highlighting key attributes of your project and telling your project’s story in the digital world.

Michael N. Smith is a BIM Manager for C.W. Driver, a large general contractor in Southern California. The firm is highly regarded throughout the design and construction industry for implementation of BIM innovations on each project and for creating customized software plug-ins to increase the efficiency of the latest software releases.  Michael is also a guest author and technical editor of Mastering Navisworks 2012.  He can be reached at

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