Overview

Surveying can be difficult. Remembering what to survey and how to apply that information can be even more difficult. This page seeks to:

• illustrate the important aspects of what to survey
• how the data relates to a physical / virtual origin
• how to apply it properly

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What to Survey

There are four different types of points to survey, and each plays a different role in locking together the physical and virtual worlds. In fact,

It Is the Survey Tool that Allows you to Lock the Physical and Virtual Worlds.

The four types of surveyed points are:

• Backsite / Origin (red)
• Fiducials (orange)
• Garbage Mattes (yellow)
• Stage Props (cyan)

Once you’ve surveyed… You’ll need to convert the survey data to X, Y, Z coordinates; this can be done using our Survey Conversion Python Script.

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Backsite / Origin

Origin

The origin is defined as the position on the floor over which the total station (survey machine) sits. The origin should be in a central location with respect to the action of the scene or stage. Exact centering isn’t necessary. The origin is found by:

• Set up the total station
• level it precisely
• drop a plumb line to the floor
• That’s the origin of your virtual world!
• When you create scenes in 3D, imagine that the scene’s center is now directly related to that point on the floor!

Backsite

The backsite is the first point surveyed. This first point establishes the front facing direction. In other words, the direction from the origin to the backsite point defines the direction of the positive X axis in Previzion.

Garbage Matte

Surveying the corners of your green screen is required when you want to create garbage mattes inside Previzion. This survey data will generate the 3D positions of the corners of the garbage mattes, which are then typed into Previzion.

Hint:

• Make sure you run the survey conversion python script to generate the proper X, Y, Z point data
• These values are what is input into Previzion for garbage mattes
• Survey all corners of the green screen

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Fiducial Target

Surveying all of the fiducial targets is critical for generating a proper Intersense Constellation file.

• Each fiducial has its own ID#
• There are two sizes of targets per board (usually)
• The x, y, z position of each fiducial target is in relation to the origin and orientation of the backsite

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Stage Prop

Sometimes you’ll need to align a stage prop to a virtual element. In this case the survey data can be used to determine where int he Maya scene the stage prop exists. You’ll need to convert the survey data to X, Y, Z coordinates; this can be done using our Survey Conversion Python Script. Once the values are generated in the survey conversion python script, create locators at the coordinates defined by the stage prop survey points. Hints:

• Survey multiple points per prop, especially for round objects