Smoke domain cuts out shadows of smoke from intersecting objects when working with different layers for compositing (CYCLES) #44515

New Issue

Edmund Havran · 2015-04-26T10:41:42+02:00

Edmund Havran commented

2015-04-26 10:41:42 +02:00

System Information
Ubuntu 14.04 / Quadro 4000

Blender Version
Broken: 2.74.5 bc160d8

Short description of error
Intention was to render an object and a smoke simulation separately on different render layers for compositing with retaining the shadow on the object. This works fine when object and domain do not intersect. As soon intersection occurs, the shadow of the smoke is being cut out by the smoke domain.

Exact steps for others to reproduce the error

Open Blender and switch to Cycles.

Select the default cube and move it to scene layer two.

(On scene layer one) Add a plane, scale it up by 8 and move it -1.5 units on z-axis.

Switch to scene layer 2, select the cube and do a Quick Smoke setup. Run it with Alt+a for a few frames (about 30 or so).

On Render Layers tab activate scene layer one and two.

On the default render layer enable layer one only.

Render the scene. Shadows are being cut out.

(This step is optional) Move the plane below the smoke domain and render the scene. Now shadows are being cast properly.

I am not sure whether this collides with this bug. https://developer.blender.org/T39142

smokeShadow.blend

**System Information** Ubuntu 14.04 / Quadro 4000 **Blender Version** Broken: 2.74.5 bc160d8 **Short description of error** Intention was to render an object and a smoke simulation separately on different render layers for compositing with retaining the shadow on the object. This works fine when object and domain do not intersect. As soon intersection occurs, the shadow of the smoke is being cut out by the smoke domain. **Exact steps for others to reproduce the error** # Open Blender and switch to Cycles. # Select the default cube and move it to scene layer two. # (On scene layer one) Add a plane, scale it up by 8 and move it -1.5 units on z-axis. # Switch to scene layer 2, select the cube and do a Quick Smoke setup. Run it with Alt+a for a few frames (about 30 or so). # On Render Layers tab activate scene layer one and two. # On the default render layer enable layer one only. # Render the scene. Shadows are being cut out. # (This step is optional) Move the plane below the smoke domain and render the scene. Now shadows are being cast properly. I am not sure whether this collides with this bug. https://developer.blender.org/T39142 [smokeShadow.blend](https://archive.blender.org/developer/F166909/smokeShadow.blend) ![smokeShadow1.jpg](https://archive.blender.org/developer/F166910/smokeShadow1.jpg) ![smokeShadow2.jpg](https://archive.blender.org/developer/F166911/smokeShadow2.jpg)

Edmund Havran commented

2015-04-26 10:41:42 +02:00

Changed status to: 'Open'

Edmund Havran commented

2015-04-26 10:41:42 +02:00

Added subscriber: @EdmundHavran

perfection cat commented

2015-04-28 07:09:00 +02:00

Added subscriber: @sindra1961

perfection cat commented

2015-04-28 07:09:01 +02:00

I think that you think that a shadow is rendered there.
However, the part is volume of domain.
You do not include layer with domain in render layer.
Therefore data of plane are rendered.

I think of the object that a shadow is rendered which is not included in render layer to be it oddly personally.

I think that you think that a shadow is rendered there. However, the part is volume of domain. You do not include layer with domain in render layer. Therefore data of plane are rendered. I think of the object that a shadow is rendered which is not included in render layer to be it oddly personally.

Sergey Sharybin commented

2015-04-28 09:17:43 +02:00

Changed status from 'Open' to: 'Archived'

Sergey Sharybin closed this issue

2015-04-28 09:17:43 +02:00

Sergey Sharybin self-assigned this 2015-04-28 09:17:43 +02:00

Sergey Sharybin commented

2015-04-28 09:17:43 +02:00

The purpose of render layers is to be able to combine them together and have full scene as a result. You've got single render layer which only includes one of the scene layers and pipeline is actually expecting you to have second render layer with the remained scene layer on it in order to have final result. And the reason you've got that "cutout" is because volume is kind of transparent and will be alpha-overed on top of the plane. Trying to have some sort of shadow is probably possible, but quite difficult, especially if you'll be combining image back.

If you don't need some objects to influence render at all, exclude corresponding scene layer.

Thanks for the report, but i don't really see bug here.

The purpose of render layers is to be able to combine them together and have full scene as a result. You've got single render layer which only includes one of the scene layers and pipeline is actually expecting you to have second render layer with the remained scene layer on it in order to have final result. And the reason you've got that "cutout" is because volume is kind of transparent and will be alpha-overed on top of the plane. Trying to have some sort of shadow is probably possible, but quite difficult, especially if you'll be combining image back. If you don't need some objects to influence render at all, exclude corresponding scene layer. Thanks for the report, but i don't really see bug here.

Edmund Havran commented

2015-04-28 18:59:01 +02:00

Hello Sergey,

Thank you for the detailed explanation. This helped me to understand the pipeline a bit better. I really thought it was bug.

Regards

Hello Sergey, Thank you for the detailed explanation. This helped me to understand the pipeline a bit better. I really thought it was bug. Regards

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Smoke domain cuts out shadows of smoke from intersecting objects when working with different layers for compositing (CYCLES) #44515

Open Blender and switch to Cycles.

Select the default cube and move it to scene layer two.

(On scene layer one) Add a plane, scale it up by 8 and move it -1.5 units on z-axis.

Switch to scene layer 2, select the cube and do a Quick Smoke setup. Run it with Alt+a for a few frames (about 30 or so).

On Render Layers tab activate scene layer one and two.

On the default render layer enable layer one only.

Render the scene. Shadows are being cut out.

(This step is optional) Move the plane below the smoke domain and render the scene. Now shadows are being cast properly.