Why do different render engines generate different z pass?
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I've been using Blender to generate depth maps using z pass. I notice that the z pass generated by different render engines are different, which made me a bit confused. My feeling is that the z pass generated by Cycle render denotes distance from a given pixel to the camera center while Blender render generates an orthogonal distance to the camera plane. Do I understand it correctly? Is so, is there a way to change such behavior for both render modes?
As an example, the bottom area of the model is a flat surface, to which the camera is perpendicularly pointed. Below are the nodes I use to normalize and visualize the z pass data (Viewer node is used to save the depth map).
Z pass with Cycles render:
Z pass with blender render (everywhere same value in the bottom part):
cycles rendering blender-render render-passes
asked 9 hours ago
DingLuoDingLuo
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DingLuo is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
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add a comment |
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I've been using Blender to generate depth maps using z pass. I notice that the z pass generated by different render engines are different, which made me a bit confused. My feeling is that the z pass generated by Cycle render denotes distance from a given pixel to the camera center while Blender render generates an orthogonal distance to the camera plane. Do I understand it correctly? Is so, is there a way to change such behavior for both render modes?
As an example, the bottom area of the model is a flat surface, to which the camera is perpendicularly pointed. Below are the nodes I use to normalize and visualize the z pass data (Viewer node is used to save the depth map).
Z pass with Cycles render:
Z pass with blender render (everywhere same value in the bottom part):
cycles rendering blender-render render-passes
asked 9 hours ago
DingLuoDingLuo
262
New contributor
DingLuo is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
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$begingroup$
Read this related link: Precision of z coordinate
$endgroup$
– cegaton
8 hours ago
$begingroup$
Also related: Cycles generates distorted depth
$endgroup$
– cegaton
8 hours ago
add a comment |
$begingroup$
I've been using Blender to generate depth maps using z pass. I notice that the z pass generated by different render engines are different, which made me a bit confused. My feeling is that the z pass generated by Cycle render denotes distance from a given pixel to the camera center while Blender render generates an orthogonal distance to the camera plane. Do I understand it correctly? Is so, is there a way to change such behavior for both render modes?
As an example, the bottom area of the model is a flat surface, to which the camera is perpendicularly pointed. Below are the nodes I use to normalize and visualize the z pass data (Viewer node is used to save the depth map).
Z pass with Cycles render:
Z pass with blender render (everywhere same value in the bottom part):
cycles rendering blender-render render-passes
asked 9 hours ago
DingLuoDingLuo
262
New contributor
DingLuo is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$endgroup$
I've been using Blender to generate depth maps using z pass. I notice that the z pass generated by different render engines are different, which made me a bit confused. My feeling is that the z pass generated by Cycle render denotes distance from a given pixel to the camera center while Blender render generates an orthogonal distance to the camera plane. Do I understand it correctly? Is so, is there a way to change such behavior for both render modes?
As an example, the bottom area of the model is a flat surface, to which the camera is perpendicularly pointed. Below are the nodes I use to normalize and visualize the z pass data (Viewer node is used to save the depth map).
Z pass with Cycles render:
Z pass with blender render (everywhere same value in the bottom part):
cycles rendering blender-render render-passes
cycles rendering blender-render render-passes
asked 9 hours ago
DingLuoDingLuo
262
New contributor
DingLuo is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 9 hours ago
DingLuoDingLuo
262
New contributor
DingLuo is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 9 hours ago
DingLuoDingLuo
262
New contributor
DingLuo is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 9 hours ago
DingLuoDingLuo
262
asked 9 hours ago
DingLuoDingLuo
262
262
New contributor
DingLuo is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
New contributor
DingLuo is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
DingLuo is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$begingroup$
Read this related link: Precision of z coordinate
$endgroup$
– cegaton
8 hours ago
$begingroup$
Also related: Cycles generates distorted depth
$endgroup$
– cegaton
8 hours ago
add a comment |
$begingroup$
Read this related link: Precision of z coordinate
$endgroup$
– cegaton
8 hours ago
$begingroup$
Also related: Cycles generates distorted depth
$endgroup$
– cegaton
8 hours ago
$begingroup$
Read this related link: Precision of z coordinate
$endgroup$
– cegaton
8 hours ago
$begingroup$
Read this related link: Precision of z coordinate
$endgroup$
– cegaton
8 hours ago
$begingroup$
Also related: Cycles generates distorted depth
$endgroup$
– cegaton
8 hours ago
$begingroup$
Also related: Cycles generates distorted depth
$endgroup$
– cegaton
8 hours ago
add a comment |
1 Answer
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When rendering a Z pass you are essentially creating a depth map from the camera point of view. The issue here is there is potentially infinite range of distances to represent by colors and only 256 shades of gray available to map them to, in a traditional 8 bit image you have .
It can go from zero close to the camera (unlikely there is something this close) to whichever visible object is most most distant. But there may also be a sky or "background" at a theoretical infinite distance.
There are several possible ways to map these shades of grey to the distance progression each with its own advantages.
It can be a linear mapping where detail is distributed evenly across all image, but here may also be logarithmic mappings, emphasizing detail at certain parts of the picture.
- You may want more detail at close range where image focus is likely to reside.
- The scene may require more detail at large distances if you are rendering a landscape or distant view
- You may want to use it for a mist pass requiring details at a medium range.
As far as I know would expect both Cycles and Blender Render to use the same "true distance to sensor", not a virtual orthographic plane passing through the sensor, but I may be wrong.
If that is indeed the case or you require a specific color progression or custom mapping of values you may construct your own "an artificial Z pass".
You can do so by making a basic emission shader with a circular black to white gradient mapped to the camera object.
Moving the camera should update the position. You can scale the gradient as desired to accommodate your desired distance range, and drive it through a Color Ramp for a non linear progression.
answered 9 hours ago
Duarte Farrajota RamosDuarte Farrajota Ramos
33.9k53980
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1 Answer
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$begingroup$
When rendering a Z pass you are essentially creating a depth map from the camera point of view. The issue here is there is potentially infinite range of distances to represent by colors and only 256 shades of gray available to map them to, in a traditional 8 bit image you have .
It can go from zero close to the camera (unlikely there is something this close) to whichever visible object is most most distant. But there may also be a sky or "background" at a theoretical infinite distance.
There are several possible ways to map these shades of grey to the distance progression each with its own advantages.
It can be a linear mapping where detail is distributed evenly across all image, but here may also be logarithmic mappings, emphasizing detail at certain parts of the picture.
- You may want more detail at close range where image focus is likely to reside.
- The scene may require more detail at large distances if you are rendering a landscape or distant view
- You may want to use it for a mist pass requiring details at a medium range.
As far as I know would expect both Cycles and Blender Render to use the same "true distance to sensor", not a virtual orthographic plane passing through the sensor, but I may be wrong.
If that is indeed the case or you require a specific color progression or custom mapping of values you may construct your own "an artificial Z pass".
You can do so by making a basic emission shader with a circular black to white gradient mapped to the camera object.
Moving the camera should update the position. You can scale the gradient as desired to accommodate your desired distance range, and drive it through a Color Ramp for a non linear progression.
answered 9 hours ago
Duarte Farrajota RamosDuarte Farrajota Ramos
33.9k53980
$endgroup$
add a comment |
$begingroup$
When rendering a Z pass you are essentially creating a depth map from the camera point of view. The issue here is there is potentially infinite range of distances to represent by colors and only 256 shades of gray available to map them to, in a traditional 8 bit image you have .
It can go from zero close to the camera (unlikely there is something this close) to whichever visible object is most most distant. But there may also be a sky or "background" at a theoretical infinite distance.
There are several possible ways to map these shades of grey to the distance progression each with its own advantages.
It can be a linear mapping where detail is distributed evenly across all image, but here may also be logarithmic mappings, emphasizing detail at certain parts of the picture.
- You may want more detail at close range where image focus is likely to reside.
- The scene may require more detail at large distances if you are rendering a landscape or distant view
- You may want to use it for a mist pass requiring details at a medium range.
As far as I know would expect both Cycles and Blender Render to use the same "true distance to sensor", not a virtual orthographic plane passing through the sensor, but I may be wrong.
If that is indeed the case or you require a specific color progression or custom mapping of values you may construct your own "an artificial Z pass".
You can do so by making a basic emission shader with a circular black to white gradient mapped to the camera object.
Moving the camera should update the position. You can scale the gradient as desired to accommodate your desired distance range, and drive it through a Color Ramp for a non linear progression.
answered 9 hours ago
Duarte Farrajota RamosDuarte Farrajota Ramos
33.9k53980
$endgroup$
add a comment |
$begingroup$
When rendering a Z pass you are essentially creating a depth map from the camera point of view. The issue here is there is potentially infinite range of distances to represent by colors and only 256 shades of gray available to map them to, in a traditional 8 bit image you have .
It can go from zero close to the camera (unlikely there is something this close) to whichever visible object is most most distant. But there may also be a sky or "background" at a theoretical infinite distance.
There are several possible ways to map these shades of grey to the distance progression each with its own advantages.
It can be a linear mapping where detail is distributed evenly across all image, but here may also be logarithmic mappings, emphasizing detail at certain parts of the picture.
- You may want more detail at close range where image focus is likely to reside.
- The scene may require more detail at large distances if you are rendering a landscape or distant view
- You may want to use it for a mist pass requiring details at a medium range.
As far as I know would expect both Cycles and Blender Render to use the same "true distance to sensor", not a virtual orthographic plane passing through the sensor, but I may be wrong.
If that is indeed the case or you require a specific color progression or custom mapping of values you may construct your own "an artificial Z pass".
You can do so by making a basic emission shader with a circular black to white gradient mapped to the camera object.
Moving the camera should update the position. You can scale the gradient as desired to accommodate your desired distance range, and drive it through a Color Ramp for a non linear progression.
answered 9 hours ago
Duarte Farrajota RamosDuarte Farrajota Ramos
33.9k53980
$endgroup$
When rendering a Z pass you are essentially creating a depth map from the camera point of view. The issue here is there is potentially infinite range of distances to represent by colors and only 256 shades of gray available to map them to, in a traditional 8 bit image you have .
It can go from zero close to the camera (unlikely there is something this close) to whichever visible object is most most distant. But there may also be a sky or "background" at a theoretical infinite distance.
There are several possible ways to map these shades of grey to the distance progression each with its own advantages.
It can be a linear mapping where detail is distributed evenly across all image, but here may also be logarithmic mappings, emphasizing detail at certain parts of the picture.
- You may want more detail at close range where image focus is likely to reside.
- The scene may require more detail at large distances if you are rendering a landscape or distant view
- You may want to use it for a mist pass requiring details at a medium range.
As far as I know would expect both Cycles and Blender Render to use the same "true distance to sensor", not a virtual orthographic plane passing through the sensor, but I may be wrong.
If that is indeed the case or you require a specific color progression or custom mapping of values you may construct your own "an artificial Z pass".
You can do so by making a basic emission shader with a circular black to white gradient mapped to the camera object.
Moving the camera should update the position. You can scale the gradient as desired to accommodate your desired distance range, and drive it through a Color Ramp for a non linear progression.
answered 9 hours ago
Duarte Farrajota RamosDuarte Farrajota Ramos
33.9k53980
edited 7 hours ago
answered 9 hours ago
Duarte Farrajota RamosDuarte Farrajota Ramos
33.9k53980
answered 9 hours ago
Duarte Farrajota RamosDuarte Farrajota Ramos
33.9k53980
answered 9 hours ago
Duarte Farrajota RamosDuarte Farrajota Ramos
33.9k53980
33.9k53980
add a comment |
add a comment |
DingLuo is a new contributor. Be nice, and check out our Code of Conduct.
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$begingroup$
Read this related link: Precision of z coordinate
$endgroup$
– cegaton
8 hours ago
$begingroup$
Also related: Cycles generates distorted depth
$endgroup$
– cegaton
8 hours ago