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NeonZ
02-21-2019, 09:39 PM
I'm working with the Render_Buffers-Light_Bffers-Piranha_Aliean.lws scene file from the sample content in both 2018.0.7 and 2019.0.1 and noticed that these two buffers output black during F9 and F10 renders. In Layout, the buffers look fine in VPR. Any idea why this is happening? I saw a thread from early 2018 about this same thing, but there wasn't any resolution recommended. The other buffers in this scene appear to render out just fine. Very odd behavior.

Thomas Leitner
02-22-2019, 01:48 AM
I'm working with the Render_Buffers-Light_Bffers-Piranha_Aliean.lws scene file from the sample content in both 2018.0.7 and 2019.0.1 and noticed that these two buffers output black during F9 and F10 renders. In Layout, the buffers look fine in VPR. Any idea why this is happening? I saw a thread from early 2018 about this same thing, but there wasn't any resolution recommended. The other buffers in this scene appear to render out just fine. Very odd behavior.
Hi Martin,
this is the way how it was indent to work. Any light buffer will have their contribution removed from the main buffer. In this scene all Diffuse_Direct and Specular_Direct contribution is in the light buffers so nothing left for the main buffers.

ciao
Thomas

MonroePoteet
02-22-2019, 08:26 AM
I don't really know what to expect from these buffers (and thanks Thomas Leitner for some explanation!), but I found that if I add a Distant Light close to the nearer "beast" and from the same direction as the Camera, these buffers show non-black. From the descriptions of the buffers, these are for light rays that are "reflected" directly into the camera. In the LW2019 content scene, all the lights are *behind* the subjects from the Camera's point of view, and the one Spherical light which is in front of them is below them and so wouldn't have much, if any rays going from the light sphere, bouncing off the subject and going directly into the camera.

Just a guess, though!

mTp

NeonZ
02-22-2019, 03:20 PM
Thanks for this information. If I turn off the light buffers, the Diffuse_Direct and Specular_Direct buffers render out as originally expected. When the light buffers are re-enabled, those same buffers return to outputting black (as now expected!) I haven't worked a lot with buffers yet, so I'm glad to get a better handle on this.

Thomas Leitner
02-23-2019, 04:56 AM
I don't really know what to expect from these buffers (and thanks Thomas Leitner for some explanation!), but I found that if I add a Distant Light close to the nearer "beast" and from the same direction as the Camera, these buffers show non-black. From the descriptions of the buffers, these are for light rays that are "reflected" directly into the camera. In the LW2019 content scene, all the lights are *behind* the subjects from the Camera's point of view, and the one Spherical light which is in front of them is below them and so wouldn't have much, if any rays going from the light sphere, bouncing off the subject and going directly into the camera.

Just a guess, though!

mTp
Hi,
the Diffuse_Direct buffer, for example, contains all direct lit surfaces. With Light Groups you can split this buffer up corresponding to the individual lights. As a result, the chosen light component is then missing in the "global" Diffuse_Direct buffer. Now you can manipulate the direct light component of this light seperatly in compositing. This works for the direct buffer of Clearcoat, SSS, Sheen, Specular, Translucency, Volumetric and Volumetric_Light not for the indirect light components like bounced light.

ciao
Thomas

MonroePoteet
02-23-2019, 09:11 AM
Hi,

Thanks for the additional explanation! I don't do any sort of complex compositing, but I can see how these buffer breakdowns would be essential for fine-tuning a desired look in post, or matching the look of live action footage, etc. When I get the time (and inclination) it'll be fun to experiment with the options.

Thanks again,
mTp