The GEOMETRY Workflow - 3D Postproduction: Stereoscopic Workflows and Techniques - page 99

The Geometry Review
The most risk-reducing activity a post team can undertake is geometry review
of all footage entering postproduction. An early review of 3D footage can help
determine which shots can bypass the geometry workl ow, which shots can be
used with what degree of additional geometry work, which shots will need help
from Visual Effects, and which shots should be omitted, modii ed or re-shot.
The purpose of the review is to verify that the geometry (in terms of spatial
and temporal synchronization) of every shot to be used in the show is correct
per target specii cation for good 3D. On some shows teams quickly identify
and resolve geometry issues. Some post teams are fortunate enough to have
the experience, tools and good fortune that result in zero or minimal geometry
issues in imagery bound for post. But on most shows, troubleshooting geometry
issues uses up precious resources that teams could otherwise put toward creative
work. Geometry issues might occur in just a few shots, or your show might
require multiple shot-by-shot geometry changes.
Each issue has a specii c technique associated with it that we discuss below. In
addition to these practical solutions, an early review of footage with a person
qualii ed to evaluate geometry can help identify some of these errors. If you are
receiving new 3D material, you must do a geometry review with an experienced 3D
practitioner. Otherwise, you risk severely underestimating the resources required
to deliver the show. Geometry reviews should be included in your post planning
along with team reviews, client reviews and other scheduled sessions.
Geometry teams spot and record errors in a Geometry Review Report in terms of:
• time (when does it occur? Does it occur identically in L and R?)
• space (where does it occur in the 3D frame?)
• severity (visual impact of the uncorrected error on audience's experience.)
• complexity (how difi cult each error is to correct.)
• coni dence (how certain the team is that they can correct the error.)
So the real challenge of 3D post is when several issues occur in the same shot
or sequence. The trick here from a project management standpoint is making
sure that the latest geometry decisions are included/concatenated correctly
with other decision lists (editorial, depth, color, visual effects) into the show
master. Stereography experience and expertise is critical in the geometry
workl ow. The situation is not just that geometry issues occur; it is that these