Night time rendering
On Jun 3, 2005, at 4:41 PM, Graeme Mair
wrote:
Hi all
Since things are a bit quiet round
these parts here's a Strata related question.
In the next two weeks or so I will have
to do a night time rendering of a building we are working on. I have to montage
the new building into an existing night time context photo and I was wondering
how best to go about doing this using Strata and Photoshop.
The boss would like to see the lights
inside the building illuminating the existing street and I was wondering if I
can use shadow catcher in Strata to do this or is it simpler to fake it in
photoshop?
Your mantra should be "Photoshop Layers &
render passes..."
If you can take a nighttime shot from the same location and angle as the posted one, and there is no pre-existing light coming from that area, then you are off to a pretty good start. The light will be "reflected" on the street only if it is wet, and beyond that will only spill out a few meters from the building itself.
Assuming you can already do the nighttime render of the building, set up your scene again from the same camera with a completely refective ground plane to stand in for the street and only the "interior" lights on, then render and composite that over the wet street in places. After that, render the scene again with a completely matte white groundplane and no ambient to get the lightspill from the interior onto the street and sidewalks. To make a perfect mask for this, raytrace a "mask" pass with the entire building matte black, and the ground plane a glowing white (with no lights on at all).
Then stack the layers in Photoshop and play with blending modes and opacities. If you want to get really fancy, shoot a second, longer exposure (overbright) when you take the initial site "nighttime" exposure so that the ground is already "lit" to some degree in that shot and use the lightspill rendering as a mask between it and the properly exposed background.
Shadow catcher really doesn't enter into the equation in my workflow... but Photoshop and Strata do.
-Mark
If you can take a nighttime shot from the same location and angle as the posted one, and there is no pre-existing light coming from that area, then you are off to a pretty good start. The light will be "reflected" on the street only if it is wet, and beyond that will only spill out a few meters from the building itself.
Assuming you can already do the nighttime render of the building, set up your scene again from the same camera with a completely refective ground plane to stand in for the street and only the "interior" lights on, then render and composite that over the wet street in places. After that, render the scene again with a completely matte white groundplane and no ambient to get the lightspill from the interior onto the street and sidewalks. To make a perfect mask for this, raytrace a "mask" pass with the entire building matte black, and the ground plane a glowing white (with no lights on at all).
Then stack the layers in Photoshop and play with blending modes and opacities. If you want to get really fancy, shoot a second, longer exposure (overbright) when you take the initial site "nighttime" exposure so that the ground is already "lit" to some degree in that shot and use the lightspill rendering as a mask between it and the properly exposed background.
Shadow catcher really doesn't enter into the equation in my workflow... but Photoshop and Strata do.
-Mark
Posted: Fri - June 3, 2005 at 04:44 PM
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Published On: Jan 19, 2006 02:04 PM
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Published On: Jan 19, 2006 02:04 PM