Discontinuity with smoke volume and transparent plane #51976

New Issue

Vyacheslav Changhai · 2017-07-06T09:40:14+02:00

2017-07-06 09:40:14 +02:00

{F653536}System Information
Operating system and graphics card

Blender Version
Broken: (example: 2.69.7 4b206af, see splash screen)
Worked: (optional)

Short description of error

Exact steps for others to reproduce the error
Based on a (as simple as possible) attached .blend file with minimum amount of steps

![Снимок.PNG](https://archive.blender.org/developer/F653530/Снимок.PNG) ![Снимок1.PNG](https://archive.blender.org/developer/F653533/Снимок1.PNG) {[F653536](https://archive.blender.org/developer/F653536/Снимок.PNG)}**System Information** Operating system and graphics card **Blender Version** Broken: (example: 2.69.7 4b206af, see splash screen) Worked: (optional) **Short description of error** **Exact steps for others to reproduce the error** Based on a (as simple as possible) attached .blend file with minimum amount of steps

Vyacheslav Changhai commented

2017-07-06 09:40:14 +02:00

Changed status to: 'Open'

Vyacheslav Changhai commented

2017-07-06 09:40:14 +02:00

Added subscriber: @Vyacheslav

Vyacheslav Changhai commented

2017-07-06 09:43:35 +02:00

Image with transparency

Vyacheslav Changhai commented

2017-07-06 10:05:06 +02:00

This comment was removed by @Vyacheslav-8

*This comment was removed by @Vyacheslav-8*

Fable Fox commented

2017-07-06 10:19:08 +02:00

Added subscriber: @fablefox

Fable Fox commented

2017-07-06 10:19:08 +02:00

which blender version?
can you provide a simple scene that can reproduce that effect?
are you rendering on CPU or GPU? which driver version?

- which blender version? - can you provide a simple scene that can reproduce that effect? - are you rendering on CPU or GPU? which driver version?

Vyacheslav Changhai commented

2017-07-07 06:10:20 +02:00

2,78{F654307}
CPU

2,78{[F654307](https://archive.blender.org/developer/F654307/dancer7.blend)} CPU

Hans Peter commented

2017-07-12 15:18:53 +02:00

Added subscriber: @chnuspi1234

Hans Peter commented

2017-07-12 15:18:53 +02:00

Changed status from 'Open' to: 'Resolved'

Hans Peter closed this issue

2017-07-12 15:18:53 +02:00

Hans Peter self-assigned this 2017-07-12 15:18:53 +02:00

Hans Peter commented

2017-07-12 15:18:53 +02:00

Although you did not pack any images or smoke cache files with the blend file provided, I was able to reproduce this effect with a simple replacement image:
That said, I believe this is the intended behaviour and not an error. The difference in lighting probably occurs because of Cycles having to render the reflection of a transparent image versus the reflection of the sky.

You can fix this issue with this slightly sophisticated workaround:

Increase samples
Enjoy

{F659598}No difference visible already with 20 samples instead of 4.

On a more serious note:
It took me a solid 10 minutes to even figure out what you were trying to do. Please include a description of the error next time. The time it takes you to fill out this template will be well worth it for everyone else.
Also please use a descriptive title and not something that could apply to literally anything. Thanks.

If you only wanted an answer to your question in the title ("Why is that?"), this is not the appropriate place for posting.

Although you did not pack any images or smoke cache files with the blend file provided, I was able to reproduce this effect with a simple replacement image: ![image.png](https://archive.blender.org/developer/F659611/image.png) That said, I believe this is the intended behaviour and not an error. The difference in lighting probably occurs because of Cycles having to render the reflection of a transparent image versus the reflection of the sky. You can fix this issue with this slightly sophisticated workaround: - Increase samples - Enjoy {[F659598](https://archive.blender.org/developer/F659598/complicated_fix.png)}*No difference visible already with 20 samples instead of 4.* **On a more serious note:** It took me a solid 10 minutes to even figure out what you were trying to do. Please include a description of the error next time. The time it takes you to fill out this template will be well worth it for everyone else. Also please use a descriptive title and not something that could apply to literally anything. Thanks. If you only wanted an answer to your question in the title ("Why is that?"), this is not the appropriate place for posting.

Brecht Van Lommel commented

2017-07-12 15:23:08 +02:00

Added subscriber: @brecht

Brecht Van Lommel commented

2017-07-12 15:23:08 +02:00

Changed status from 'Resolved' to: 'Open'

Brecht Van Lommel reopened this issue

2017-07-12 15:23:08 +02:00

Brecht Van Lommel commented

2017-07-12 15:23:08 +02:00

Please leave it to developers to close reports. I suspect there might actually be a bug here, specifically related to the smoke volume which is not in your test render.

Brecht Van Lommel changed title from ~~Why is that?~~ to Discontinuity with smoke volume and transparent plane

2017-07-12 15:23:44 +02:00

Hans Peter was unassigned by Brecht Van Lommel

2017-07-12 15:23:44 +02:00

Hans Peter commented

2017-07-12 15:28:09 +02:00

Sorry for closing this, I thought someone would have to approve it.

Also I didn't have the smoke volume in my render, but added in a cube with Volume Scattering if that changes anything.

Sorry again for interfering.

Sorry for closing this, I thought someone would have to approve it. Also I didn't have the smoke volume in my render, but added in a cube with Volume Scattering if that changes anything. Sorry again for interfering.

Brecht Van Lommel commented

2017-07-12 15:37:31 +02:00

No problem, help is always welcome, it's not always immediately clear what the rules are.

Hans Peter commented

2017-07-12 16:01:30 +02:00

While trying to reproduce this error, I found out it happened because in the Object Properties under Cycles Settings, the Glossy option was disabled.

So this does pretty much what it should do, I guess.

Hope I could save you some time with this.

While trying to reproduce this error, I found out it happened because in the Object Properties under Cycles Settings, the **Glossy option was disabled**. ![glossy.png](https://archive.blender.org/developer/F659632/glossy.png) So this does pretty much what it should do, I guess. Hope I could save you some time with this.

Brecht Van Lommel commented

2017-07-20 17:02:47 +02:00

Changed status from 'Open' to: 'Archived'

Brecht Van Lommel closed this issue

2017-07-20 17:02:47 +02:00

Brecht Van Lommel self-assigned this 2017-07-20 17:02:47 +02:00

Brecht Van Lommel commented

2017-07-20 17:02:47 +02:00

Thanks for figuring that out, that explains it indeed, no bug here then.

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Discontinuity with smoke volume and transparent plane #51976