Techniques for automating stereo settings for stereoscopic computer animation

1. A computer-implemented method for determining bounded-parallax constraints for placement of a pair of stereoscopic cameras within a computer-generated scene, the pair of stereoscopic cameras viewing a computer-generated object within the computer-generated scene and the pair of stereoscopic cameras having a focal length, the method comprising:

determining an initial near-parallax value based on the focal length and a minimum scene depth, wherein the minimum scene depth is the distance from the pair of cameras to a nearest point of interest in the computer-generated scene;

determining an initial far-parallax value based on the focal length;

obtaining a range of focal lengths;

calculating a scaled near-parallax value based on the initial near-parallax value and the range of focal lengths;

calculating a scaled far-parallax value based on the initial far-parallax value and the range of focal lengths;

obtaining a stereo-volume value, wherein the stereo-volume value represents a percentage of parallax;

obtaining a stereo-shift value, wherein the stereo-shift value represents a distance across one of:

an area associated with a sensor of the pair of stereoscopic cameras; and

a screen adapted to depict a stereoscopic image of the computer-generated scene;

calculating a creative near-parallax value based on the stereo-shift value and the product of the stereo-volume and the scaled near-parallax value;

calculating a creative far-parallax value based on the stereo-shift value and the product of the stereo-volume and the scaled far-parallax value;

storing, in a computer memory, the creative near-parallax value and the creative far-parallax value as the bounded-parallax constraints for the placement of the pair of stereoscopic cameras.

2. The computer-implemented method of claim 1 , further comprising:

positioning each camera of the pair of stereoscopic cameras relative to each other based on the bounded-parallax constraints;

creating a stereoscopic image of the computer-generated scene with the pair of stereoscopic cameras; and

storing, in the computer memory, the stereoscopic image.

3. The computer-implemented method of claim 1 , further comprising:

calculating a camera separation value and a convergence value for the pair of stereoscopic cameras based on the bounded-parallax constraints; and

storing, in the computer memory, the camera separation value and the convergence value.

4. The computer-implemented method of claim 3 , further comprising:

positioning each camera of the pair of stereoscopic cameras relative to each other within the computer-generated scene based on the camera separation value and the convergence value.

5. The computer-implemented method of claim 3 , further comprising:

positioning a camera sensor of the pair of stereoscopic cameras within the computer-generated scene based on the camera separation value and the convergence value.

6. The computer-implemented method of claim 1 , wherein the nearest point of interest in the computer-generated scene is determined by determining the closest point on the computer-generated object within the scene over an area that corresponds to a middle portion of a camera sensor of the pair of stereoscopic cameras.

7. The computer-implemented method of claim 6 , wherein the area corresponds to a middle ⅔ area of the camera sensor.

8. The computer-implemented method of claim 1 , wherein the nearest point of interest in the computer-generated scene is determined by:

generating a depth buffer array of depth pixels having a depth value, each depth value of the depth buffer array measured from a camera sensor of the pair of stereoscopic cameras to a closest point on the computer-generated object in the computer-generated scene along a ray projected from the sensor through the depth pixel,

calculating the nearest point of interest in the computer-generated scene based on the minimum depth value over an area that corresponds to a middle portion of the camera sensor.

9. The computer-implemented method of claim 1 , wherein the distance from the pair of cameras to the nearest point of interest in the computer-generated scene is measured relative to a midpoint between the pair of cameras.

10. The computer-implemented method of claim 1 , wherein:

if the focal length is less than a lower-bound value,

calculating the scaled near-parallax value as the near-parallax value times a ratio of the lower-bound value divided by the focal length, and

calculating the scaled far-parallax value as the far-parallax value times the ratio of the lower-bound value divided by the focal length; and

if the focal length is greater than an upper-bound value,

calculating the scaled near-parallax value as the near-parallax value times the ratio of the upper-bound value divided by the focal length, and

calculating the scaled far-parallax value as the far-parallax value times the ratio of the upper-bound value divided by the focal length.

11. The computer-implemented method of claim 1 , wherein the stereo-volume value is specified as a percentage value such that: values greater than 100 percent correspond to an amplification of a stereo effect, and values less than 100 percent correspond to an attenuation of the stereo effect, wherein the stereo effect represents an overall amount of parallax in a stereoscopic image of the computer-generated scene.

12. The computer-implemented method of claim 1 , further comprising:

obtaining a timeline of the film sequence, the timeline comprising a plurality of time entries;

for the at least two time entries, calculate a script-adjusted near-parallax value based on the stereo-shift value and the product of the stereo-volume and the scaled near-parallax value;

for the at least two time entries, calculate a script-adjusted far-parallax value based on the stereo-shift value and the product of the stereo-volume and the scaled far-parallax value; and

storing, in the computer memory, the script-adjusted near-parallax value and script-adjusted far-parallax value.

13. A computer system for determining bounded-parallax constraints for placement of a pair of stereoscopic cameras within a computer-generated scene, the pair of stereoscopic cameras viewing a computer-generated object within the computer-generated scene and the pair of stereoscopic cameras having a focal length, the system comprising:

a memory;

a processor for executing computer-readable instructions, the instructions for:

determining an initial near-parallax value based on the focal length and a minimum scene depth, wherein the minimum scene depth is the distance from the pair of cameras to a nearest point of interest in the computer-generated scene;

determining an initial far-parallax value based on the focal length;

obtaining a range of focal lengths;

calculating a scaled near-parallax value based on the initial near-parallax value and the range of focal lengths;

calculating a scaled far-parallax value based on the initial far-parallax value and the range of focal lengths;

obtaining a stereo-volume value, wherein the stereo-volume value represents a percentage of parallax;

obtaining a stereo-shift value, wherein the stereo-shift value represents a distance across one of:

an area associated with a sensor of the pair of stereoscopic cameras, and

a screen adapted to depict a stereoscopic image of the computer-generated scene;

calculating a creative near-parallax value based on the stereo-shift value and the product of the stereo-volume and the scaled near-parallax value;

calculating a creative far-parallax value based on the stereo-shift value and the product of the stereo-volume and the scaled far-parallax value;

storing, in the memory, the creative near-parallax value and the creative far-parallax value as the bounded-parallax constraints for the placement of the pair of stereoscopic cameras.

14. The computer system of claim 13 , further comprising:

positioning each camera of the pair of stereoscopic cameras relative to each other based on the bounded-parallax constraints;

creating a stereoscopic image of the computer-generated scene with the pair of stereoscopic cameras; and

storing, in the memory, the stereoscopic image.

15. The computer system of claim 13 , further comprising:

calculating a camera separation value and a convergence value for the pair of stereoscopic cameras based on the bounded-parallax constraints; and

storing, in the memory, the camera separation value and the convergence value.

16. The computer system of claim 13 , wherein the nearest point of interest in the computer-generated scene is determined by determining the closest point on a computer-generated object within the scene over an area that corresponds to a middle portion of a camera sensor of the pair of stereoscopic cameras.

17. The computer system of claim 13 , wherein the distance from the pair of cameras to the nearest point of interest in the computer-generated scene is measured relative to a midpoint between the pair of stereoscopic cameras.

18. The computer system of claim 13 , wherein:

if the focal length is less than a lower-bound value,

calculating the scaled near-parallax value as the near-parallax value times a ratio of the lower-bound value divided by the focal length, and

calculating the scaled far-parallax value as the far-parallax value times the ratio of the lower-bound value divided by the focal length; and

if the focal length is greater than an upper-bound value,

calculating the scaled near-parallax value as the near-parallax value times the ratio of the upper-bound value divided by the focal length, and

calculating the scaled far-parallax value as the far-parallax value times the ratio of the upper-bound value divided by the focal length.

19. A non-transitory computer-readable storage medium including computer-readable instructions that when executed on a computer processor cause the computer processor to determine bounded-parallax constraints for placement of a pair of stereoscopic cameras within a computer-generated scene, the pair of stereoscopic cameras viewing a computer-generated object within the computer-generated scene and the pair of stereoscopic cameras having a focal length, the instructions comprising:

determining an initial near-parallax value based on the focal length and a minimum scene depth, wherein the minimum scene depth is the distance from the pair of cameras to a nearest point of interest in the computer-generated scene;

determining an initial far-parallax value based on the focal length;

obtaining a range of focal lengths;

calculating a scaled near-parallax value based on the initial near-parallax value and the range of focal lengths;

calculating a scaled far-parallax value based on the initial far-parallax value and the range of focal lengths;

obtaining a stereo-volume value, wherein the stereo-volume value represents a percentage of parallax;

obtaining a stereo-shift value, wherein the stereo-shift value represents a distance across one of:

an area associated with a sensor of the pair of stereoscopic cameras, and

a screen adapted to depict a stereoscopic image of the computer-generated scene;

calculating a creative near-parallax value based on the stereo-shift value and the product of the stereo-volume and the scaled near-parallax value;

calculating a creative far-parallax value based on the stereo-shift value and the product of the stereo-volume and the scaled far-parallax value; and

storing, in a computer memory, the creative near-parallax value and the creative farparallax value as the bounded-parallax constraints for the placement of the pair of stereoscopic cameras.

20. The non-transitory computer-readable medium of claim 19 , further comprising:

Positioning each camera of the pair of stereoscopic cameras relative to each other based on the bounded-parallax constraints;

creating a stereoscopic image of the computer-generated scene with the pair of stereoscopic cameras; and

storing, in the computer memory, the stereoscopic image.

21. The non-transitory computer-readable medium of claim 19 , further comprising:

calculating a camera separation value and a convergence value for the pair of stereoscopic cameras based on the bounded-parallax constraints; and

storing, in the computer memory, the camera separation value and the convergence value.

22. The non-transitory computer-readable medium of claim 19 , wherein the nearest point of interest in the computer-generated scene is determined by determining the closest point on a computer-generated object within the scene over an area that corresponds to a middle portion of a camera sensor of the pair of stereoscopic cameras.

23. The non-transitory computer-readable medium of claim 19 , wherein the distance from the pair of cameras to the nearest point of interest in the computer-generated scene is measured relative to a midpoint between the pair of stereoscopic cameras.

24. The non-transitory computer-readable medium of claim 19 , wherein:

if the focal length is less than a lower-bound value,

calculating the scaled near-parallax value as the near-parallax value times a ratio of the lower-bound value divided by the focal length, and

calculating the scaled far-parallax value as the far-parallax value times the ratio of the lower-bound value divided by the focal length; and

if the focal length is greater than an upper-bound value,

calculating the scaled near-parallax value as the near-parallax value times the ratio of the upper-bound value divided by the focal length, and

calculating the scaled far-parallax value as the far-parallax value times the ratio of the upper-bound value divided by the focal length.