HDR
Test
30
May 2010
After
working through some training tutorials for using high dynamic range
images with Maya lighting and mental ray rendering techniques I
needed to take an afternoon to put things into practice beyond the
lessons.
I spent
the morning visiting a couple garden centres and finally got lucky
at the Polhill Garden Centre at Badgers Mount, near Sevenoaks in
Kent. I purchased a £10 20cm "gazing ball" and couldn't
wait to get home to snap some HDR photos. The surface of the ball
isn't perfect; there are some imperfections and subtle rippling
as well as a seam through the middle that warps the reflections
somewhat. My current camera is nothing special, a Canon IXUS 75,
so the quality of my light probe suitably matches :P
All
in all, my low-fi technology still allowed me to put some theory
into practice and render out a shot from Maya that uses HDR imagery
to help embed the cg elements into the scene with location-specific
lighting, provides reflections, and gets my cg another small step
closer to looking photoreal.
For
this shot I wanted to stay in Maya and practice render layers without
taking all the separate elements into an external compositing package.
- A
useBackground shader captures the shadows on the floor and lower
portion of the couch.
- A
camera projection of the original plate onto simple geometry is
used to generate the reflections of the floor, couch, and items
on the shelf in background.
- The
original plate is also projected onto some cylinder geometry for
the tripod legs in the foreground to allow a little box to sit
behind the tripod in real 3D space.
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