Mantaflow does not render flame when flow source is hidden from Renders #72192

New Issue

ifurkend · 2019-12-05T10:43:38+01:00

ifurkend commented

2019-12-05 10:43:38 +01:00

System Information
Operating system: Windows-7-6.1.7601-SP1 64 Bits
Graphics card: GeForce GTX 1060 6GB/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 388.13

Blender Version
Broken: version: 2.82 (sub 1), branch: fluid-mantaflow, commit date: 2019-11-26 22:21, hash: 0ca44974c9
Worked: (optional)

Short description of error
Mantaflow does not render the flame but only smokes of "fire + smoke" if the flow source is hidden from renders. I hide the source because it is just an emitter not intended to be visible in the final render.

Exact steps for others to reproduce the error

Select the cube in the default new project, create "quick smoke" then change the source flow type to "fire + smoke".
Select the domain object, bake data.
Increase Blackbody Intensity value of the Smoke Domain Material, like 10.
Render the effect, everything is as intended.
Select the flow source, uncheck "Show in Renders" in Objects properties - Visibility.
Free the domain data and bake again.
Render again, now the flame disappear. (Notably the flame is still visible in Rendered Viewport, but not the actual render.)
Enable visibility of the flow source, rebake the domain and everything is back to normal.

**System Information** Operating system: Windows-7-6.1.7601-SP1 64 Bits Graphics card: GeForce GTX 1060 6GB/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 388.13 **Blender Version** Broken: version: 2.82 (sub 1), branch: fluid-mantaflow, commit date: 2019-11-26 22:21, hash: `0ca44974c9` Worked: (optional) **Short description of error** Mantaflow does not render the flame but only smokes of "fire + smoke" if the flow source is hidden from renders. I hide the source because it is just an emitter not intended to be visible in the final render. **Exact steps for others to reproduce the error** 1. Select the cube in the default new project, create "quick smoke" then change the source flow type to "fire + smoke". 2. Select the domain object, bake data. 3. Increase Blackbody Intensity value of the Smoke Domain Material, like 10. 4. Render the effect, everything is as intended. 5. Select the flow source, uncheck "Show in Renders" in Objects properties - Visibility. 6. Free the domain data and bake again. 7. Render again, now the flame disappear. (Notably the flame is still visible in Rendered Viewport, but not the actual render.) 8. Enable visibility of the flow source, rebake the domain and everything is back to normal.

ifurkend commented

2019-12-05 10:43:38 +01:00

Added subscriber: @ifurkend

blender-admin commented

2019-12-05 10:43:38 +01:00

#74841 was marked as duplicate of this issue

Stephen Swaney commented

2019-12-05 16:24:07 +01:00

Added subscriber: @StephenSwaney

Stephen Swaney commented

2019-12-05 16:24:07 +01:00

If I understand your steps, you uncheck Show in Renders and the object does not show in the render but does show in the viewport. This sounds like expected behavior.

If you uncheck Show in Viewports, does it disappear?

If I understand your steps, you uncheck Show in Renders and the object does not show in the render but *does* show in the viewport. This sounds like expected behavior. If you uncheck Show in Viewports, does it disappear?

ifurkend commented

2019-12-06 02:44:17 +01:00

In #72192#824583, @StephenSwaney wrote:
If I understand your steps, you uncheck Show in Renders and the object does not show in the render but does show in the viewport. This sounds like expected behavior.

If you uncheck Show in Viewports, does it disappear?

The point is only the fire is not shown but the smoke still renders. How can such inconsistency be considered "expected"?
Regarding uncheck Show in Viewports, here's the table for you.

Edit: To clarify that I don't mean changing the visibility of the Domain object,
but the source object where fire/smoke/fluid is emitted from.
Indeed changing the visibility of the Domain is expected to affect the visibility of the fire and smoke,
this is consistent with Blender 2.7.

	viewport + render	viewport only	render only	no viewport or render
already baked but change visibility before rendering	fine	fine in viewport but smoke only in render	fine	fine in viewport but smoke only in render
rebake	fine	fine in viewport but smoke only in render	nothing shown	nothing shown

Back in Blender 2.7 to create the similar fire+smoke effect,
hiding the flow source from viewport and render does not prevent either the fire or smoke from being baked and rendered.
This makes the whole situation with Mantaflow so baffling.

> In #72192#824583, @StephenSwaney wrote: > If I understand your steps, you uncheck Show in Renders and the object does not show in the render but *does* show in the viewport. This sounds like expected behavior. > > If you uncheck Show in Viewports, does it disappear? The point is only the fire is not shown but the smoke still renders. How can such inconsistency be considered "expected"? Regarding uncheck Show in Viewports, here's the table for you. Edit: To clarify that I don't mean changing the visibility of the Domain object, but the source object where fire/smoke/fluid is emitted from. Indeed changing the visibility of the Domain is expected to affect the visibility of the fire and smoke, this is consistent with Blender 2.7. | | **viewport + render** | **viewport only** | **render only** | **no viewport or render** | | -- | -- | -- | -- | -- | | **already baked but change visibility before rendering** | fine | fine in viewport but smoke only in render | fine | fine in viewport but smoke only in render | | **rebake** | fine | fine in viewport but smoke only in render | nothing shown | nothing shown | Back in Blender 2.7 to create the similar fire+smoke effect, hiding the flow source from viewport and render does not prevent either the fire or smoke from being baked and rendered. This makes the whole situation with Mantaflow so baffling.

Jacques Lucke commented

2020-01-15 12:51:13 +01:00

Added subscriber: @JacquesLucke

Jacques Lucke commented

2020-01-15 12:51:13 +01:00

Changed status from 'Needs Triage' to: 'Needs User Info'

Jacques Lucke commented

2020-01-15 12:51:13 +01:00

Is that still an issue in the latest builds from https://builder.blender.org/download/?
If yes, please prepare a very simple .blend file that makes it easier to reproduce the issue.

Is that still an issue in the latest builds from https://builder.blender.org/download/? If yes, please prepare a very simple .blend file that makes it easier to reproduce the issue.

ifurkend commented

2020-01-16 05:01:51 +01:00

In #72192#849459, @JacquesLucke wrote:
Is that still an issue in the latest builds from https://builder.blender.org/download/?
If yes, please prepare a very simple .blend file that makes it easier to reproduce the issue.

Same issues on fluid-mantaflow-blender-2.82-ed32db06c124-windows64

Mantaflow report 2020 0116.blend

> In #72192#849459, @JacquesLucke wrote: > Is that still an issue in the latest builds from https://builder.blender.org/download/? > If yes, please prepare a very simple .blend file that makes it easier to reproduce the issue. Same issues on fluid-mantaflow-blender-2.82-ed32db06c124-windows64 [Mantaflow report 2020 0116.blend](https://archive.blender.org/developer/F8281066/Mantaflow_report_2020_0116.blend)

Jacques Lucke commented

2020-01-16 10:03:46 +01:00

Changed status from 'Needs User Info' to: 'Needs Triage'

Richard Antalik commented

2020-01-16 23:38:41 +01:00

Changed status from 'Needs Triage' to: 'Confirmed'

Sebastián Barschkis was assigned by Bastien Montagne

2020-01-20 11:05:28 +01:00

Richard Antalik commented

2020-03-17 21:44:15 +01:00

Added subscriber: @JohnCox-3

Catalin commented

2020-05-21 20:10:30 +02:00

Added subscriber: @cata_cg

Maxim Ponomarov commented

2020-05-24 00:42:12 +02:00

Added subscriber: @ponomarovmax

Goury commented

2020-05-27 02:07:44 +02:00

Added subscriber: @Goury

Goury commented

2020-05-27 02:07:44 +02:00

Are there any plans to ever fix this?
Clearly this isn't how it supposed to (not) work.
It also makes preview useless, slowing down the workflow to stall.

Are there any plans to ever fix this? Clearly this isn't how it supposed to (not) work. It also makes preview useless, slowing down the workflow to stall.

Catalin commented

2020-06-02 08:03:13 +02:00

Not sure if it's a proper solution but I found a way to hide the source and maintain the fire in the render.

Select Source -> Material Properties -> Surface -> Select "Transparent BSDF"

Alternatively, you can add an Emission shader in the Volume properties (Select Source -> Material Properties -> VOLUME-> Select "Emission") and set it's color to orange or yellow. This option just reduces the visibility of the source but not in all aspects.

Hope this helps!

Not sure if it's a proper solution but I found a way to hide the source and maintain the fire in the render. Select Source -> Material Properties -> Surface -> Select "Transparent BSDF" Alternatively, you can add an Emission shader in the Volume properties (Select Source -> Material Properties -> VOLUME-> Select "Emission") and set it's color to orange or yellow. This option just reduces the visibility of the source but not in all aspects. Hope this helps!

Simon Urzua commented

2020-06-06 11:42:44 +02:00

Added subscriber: @simonurzua

Simon Urzua commented

2020-06-06 11:42:44 +02:00

Same issue here in Blender 2.83.0

Galib F. Arrieta commented

2020-06-11 05:31:32 +02:00

Added subscriber: @Galib-Arrieta

Galib F. Arrieta commented

2020-06-11 05:31:32 +02:00

Same problem here. Blender 2.83. I have a tried everything to get it working. Hiding the flow emitter only renders the smoke, the fire always remain invisible when rendering to an image or as animation.

Galib F. Arrieta commented

2020-06-11 05:42:24 +02:00

Actually, a decent workaround is to add a Principled BSDF material to the flow emitter, and set Alpha to 0. Now I see the fire in the rendered image. This is a similar solution as suggested by @cata_cg .

Georg Bernhard commented

2020-06-14 22:30:58 +02:00

Added subscriber: @gogo

Georg Bernhard commented

2020-06-14 22:30:58 +02:00

I just ran into the same problem (after a quite time-consuming bake) and the workaround (making the inflow object visible) worked. I wish it wouldn't be necessary though. I unchecked visibilities (camera, diffuse, ...)

Shamimur Rahman commented

2020-07-29 19:00:59 +02:00

Added subscriber: @shamimurrahman19

Shamimur Rahman commented

2020-07-29 19:00:59 +02:00

The problem still exists in 2.83.3

blender-admin commented

2020-08-04 18:09:03 +02:00

This issue was referenced by df28a68e70

This issue was referenced by df28a68e7009da6a1de4597ecb579236e542e170

Sebastián Barschkis commented

2020-08-04 18:09:35 +02:00

Changed status from 'Confirmed' to: 'Resolved'

Sebastián Barschkis closed this issue

2020-08-04 18:09:35 +02:00

Aaditya das commented

2020-09-08 22:57:29 +02:00

Added subscriber: @imaadityadas

Aaditya das commented

2020-09-08 22:57:29 +02:00

I got the same problem and found out that if you disable the flow object from the view port and the render the flames are not visible
so if you re-enable to show the flow object the flames appears in the renders

I got the same problem and found out that if you disable the flow object from the view port and the render the flames are not visible so if you re-enable to show the flow object the flames appears in the renders

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Mantaflow does not render flame when flow source is hidden from Renders #72192