32 bits LWF multipass alpha problem
Posted: Sat Apr 04, 2020 4:19 pm
Hello !
i'm struggling since a while to properly reproduce the beauty pass, in 32 bits lwf EXR. May i ask your help please ?
i mean, the LWF 32 bit part is not a problem. But the recomposition of the beauty pass is partly a problem. i can reproduce it but i have some alpha/edges problem, especialy when mixing with the background. i looked at the octane manual, and at andrey lebrov's tutorials.
1/ I setup the EXR octane and path, enable show passes, save beauty, multilayer file
Image color profile to linear
Tonemap type to linear
I select the beauty passes ( diffuse direct, indirect, reflexion direct, indirect, transmission, refraction, shadow ..
2/ I select the ambient light direct indirect, sun direct, indirect
3/ I set the render buffer to float(linear) as recommended by andrey lebrov
4/ In the sun settings, I enable the “imp sample”, as recommended in octane's manual, for the shadow ( although i'm not sure how to use the shadow pass ) :
Shadow Pass - This pass contains all direct light shadows calculated on the first path bounce. The pass includes sun light provided by the Daylight environment node. The Shadow pass excludes the Sky light (a.k.a Octane Sun+Sky environment) or Texture environment if the texture environment does not consist of an image. If the Environment node contains a Sky light or Texture environment that is contributed by an image texture, the pass takes the Environment node's Importance Sampling value into account. Make sure to enable Importance Sampling in the Environment node to include the Sky light or Texture environment in the Shadow pass.
Figure 4: A scene with an Octane Sun+Sky environment is rendered with a Shadow pass twice for comparison. The resulting passes with Importance sampling enable and disabled are compared
5/ I enable the “neutral response” in the camera settings, as recommended by andrey lebrov
6/ you can see that the recomposed beauty, with diffuse direct, indirect, reflexion direct, indirect, refraction are set on “add ) blend mode, inside a “pass through” group.
You can see that there’s an alpha problem on the edges …
7/ if I enable the sky background, in normal mode, there’s no more visible alpha problem BUT … the scene is all burned now.
8/ here’s how the beauty pass alone looks like, in normal mode, without alpha problem. ( multipass – 8 )
9/ With the sky background enabled, it works but the edges are strange … ( multipass – 9 )
10/ here’s how the complete render looks like in C4D octane …. The recomposed beauty is supposed to look exactly like this, but no ….
So where is anything wrong ? it’s not easy.
i attach the scene. you can put an hdri in the environment texture's octane sky.
i'm struggling since a while to properly reproduce the beauty pass, in 32 bits lwf EXR. May i ask your help please ?
i mean, the LWF 32 bit part is not a problem. But the recomposition of the beauty pass is partly a problem. i can reproduce it but i have some alpha/edges problem, especialy when mixing with the background. i looked at the octane manual, and at andrey lebrov's tutorials.
1/ I setup the EXR octane and path, enable show passes, save beauty, multilayer file
Image color profile to linear
Tonemap type to linear
I select the beauty passes ( diffuse direct, indirect, reflexion direct, indirect, transmission, refraction, shadow ..
Shadow Pass - This pass contains all direct light shadows calculated on the first path bounce. The pass includes sun light provided by the Daylight environment node. The Shadow pass excludes the Sky light (a.k.a Octane Sun+Sky environment) or Texture environment if the texture environment does not consist of an image. If the Environment node contains a Sky light or Texture environment that is contributed by an image texture, the pass takes the Environment node's Importance Sampling value into account. Make sure to enable Importance Sampling in the Environment node to include the Sky light or Texture environment in the Shadow pass.
Figure 4: A scene with an Octane Sun+Sky environment is rendered with a Shadow pass twice for comparison. The resulting passes with Importance sampling enable and disabled are compared
You can see that there’s an alpha problem on the edges …
i attach the scene. you can put an hdri in the environment texture's octane sky.
