General guidelines

• You can create survey constraints at any time, provided you have track points. However, we recommend first obtaining a proximate solution before adding constraints.
• The number of survey constraints varies depending on which constraints are appropriate for the shot. Typically, shots require no more than seven to eight constraints, but there are no limits to how many you can add.
• It’s okay to estimate constraint distances or coordinates if you are using a limited number of constraints. (There is also a Variance setting you can use to allow the solver some leeway.) However, we recommend using accurate measurements from the set if you create multiple constraints.
• Where you place survey constraints is important. Refer to Placement of Plane and Point constraints for more information.
• Adding constraints slows performance of the solver, but there is less of an impact for Registration only constraints.
• You can adjust the colors used for the objects that represent constraints. See Use the Track Display panel.

To create survey constraints

1. Open the Solve Survey control panel.
2. Select track points as you would any Maya object. (Do not select the associated 3D locators—only track points.)

   Typically, you select in the shotCamera panel or through the Outliner (listed under clip1TrackedPointVisibilityGroup > clip1TrackedPointGroup).

3. Choose the constraint you want from the LiveConstraints pull-down menu or hot box menu (press spacebar).
   NoteYou can also choose a constraint from the Constraint Type pull-down in the Solve Survey control panel. If you do, you must also click Create.

   The constraint appears as an object in the view panels:

   

4. Set the constraint’s length or location in the 3D coordinate system.

   Constraint	Settings
   Point	Use the perspective view or Channel box to orient and translate the constraint object. You may want to use the Maya snap tools to lock it onto a model.
   Distance	Enter the value in the Survey control panel.
   Plane	Use the perspective view or Channel box to orient and translate the constraint object. Refer to Placement of Plane and Point constraints for more information.
   Depth	Enter the value in the Survey control panel.

5. Optional: Modify the Variance setting if you want to allow some leeway for the solver to vary from the constraint settings.

Follow these steps to incorporate your constraints into an existing solution. Otherwise, you can start the solver again to create a new solution.

To apply survey constraints to a solution

1. Open the Solve control panel.
2. Select the current solution you think is best.
3. Click the Register or Refine button.

   Register applies the constraint to the whole solution. Refine incorporates the constraint into the shape of the solution.

Placement of Plane and Point constraints

Plane constraints extend infinitely beyond the plane that represents them. Therefore, you can move the nurbs plane object anywhere along the plane you want to constrain.

Make sure you place constraints relative to each other as they were in real world space. For example, Plane constraints for a floor and a wall should be perpendicular. Also keep in mind that the distance you use between parallel Plane constraints implies a distance constraint.

If you use Point constraints in combination with reference geometry, use the Maya snap tools to help you place the geometry into the scene.

Modify survey constraints

You can modify the values of constraints at any time. However, once the constraint is created, you cannot add or remove affiliated points. You must create a new constraint that has the desired points and delete the old constraint.