Visualizing Pyro Cache in render

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coolkalle: Member; 13 posts; Joined: March 2017; Offline

June 29, 2017 6:11 a.m.

I have created a pyro sim that I've cached out to disk and then imported back in using a FileImport node inside of a Geo node. This works fine in the scene view, I can scrub back and forth through my sim, and in conjunction with a volumevisualization node the whole thing looks just like I want it in the viewport. However, when I render my scene, my sim just shows up as a grey cube. Does anyone know how I should go about fixing this?

Attachments:
SceneView.PNG (474.2 KB)
RenderView.PNG (158.9 KB)


Enivob: Member; 2537 posts; Joined: June 2008; Offline

June 30, 2017 9:01 a.m.

Did you apply a volume based material to your new looping_cache?
You may also have to populate the material with the correct field name contained within your cached smoke, such as density or temperature.

Using Houdini Indie 20.0
Windows 11 64GB Ryzen 16 core.
nVidia 3050RTX 8BG RAM.


coolkalle: Member; 13 posts; Joined: March 2017; Offline

July 1, 2017 11:38 a.m.

Could you explain in further detail how I assign a volume based material to my cache? I tried assigning a material to the Cache by dragging out a material node from it and then used the default smokelessflames shader, but that doesn't seem to do anything. Am I using the wrong node?

Sorry for the newb questions, I'm fairly new to Houdini

Edited by coolkalle - July 1, 2017 11:39:15

Attachments:
MatCapture.PNG (675.1 KB)


jsmack: Member; 7770 posts; Joined: Sept. 2011; Offline

July 1, 2017 8:16 p.m.

Why assign the material just to heat? That won't work.


coolkalle: Member; 13 posts; Joined: March 2017; Offline

July 3, 2017 6:29 a.m.

It doesn't seem to matter which variables I pass into the material node; I've plugged every single parameter from the cache (Density, Fuel, Heat, Temperature, etc) into the material and the cache still looks the same in the viewport. The render view is also completely black.

Attachments:
matApplication.PNG (172.6 KB)


eddgarpv: Member; 64 posts; Joined: July 2005; Offline

Aug. 9, 2017 2:32 p.m.

Did you find a solution for this?
I'm having the exact same issue with a cached simulation and I can't find the problem. I'll convert to vdb and see what happens.


Enivob: Member; 2537 posts; Joined: June 2008; Offline

Aug. 15, 2017 10:08 p.m.

No, no you don't specify @density in the group, that will exclude everything. There is no group named @density. Leave the group field blank and dive inside the material and type density in to the field provided in the material.

Or just use the shelf tools, they set all that up for you.

Using Houdini Indie 20.0
Windows 11 64GB Ryzen 16 core.
nVidia 3050RTX 8BG RAM.


robsdesign: Member; 236 posts; Joined: March 2015; Offline

Aug. 17, 2017 12:44 p.m.

If you used shelf tools, have you tried using the original pyro import DOP I/O node? (Check the Load from Disk box)

To do it from scratch. Create a geo node go to material tab and assign material, dive in and delete file node. Create a DOP I/O node, set Geometry file location, check load from disk and select all the fields you need.

Rob


coolkalle: Member; 13 posts; Joined: March 2017; Offline

Aug. 30, 2017 11:53 a.m.

I got back to this issue today, but unfortunately I've yet to figure it out. I've attempted both solutions posted by Enivob and robsdesign, but my fire still doesn't get affected by the material I give it.

I can import the cached data using a DOP I/O inside of an empty geo node - It is possible to scrub back and forth through the timeline when I do this, but assigning the smokelessflames material still doesn't do anything in the viewport or the render view. I've tried changing what fields to import in the DOP I/O node, but it doesn't seem to matter which ones i pick. Any ideas?

Attachments:
DOP_IO_LoadFile.JPG (110.4 KB)
DOP_IO.JPG (110.0 KB)


A-OC: Member; 253 posts; Joined: July 2006; Offline

Aug. 30, 2017 7:23 p.m.

You need to post a scene so we can take a look


coolkalle: Member; 13 posts; Joined: March 2017; Offline

Sept. 1, 2017 8:32 a.m.

Here's the scene.

Attachments:
fireLooping.hipnc (910.9 KB)


Enivob: Member; 2537 posts; Joined: June 2008; Offline

Sept. 1, 2017 4:33 p.m.

Under the Smoke TAB Density Volume field type ‘density’, not heat.

You may want to open up a new scene. CTRL-Click on the sphere then click on the PyroFX tab and click on Flames. This will produce a working renderable pyro scene. Inspect that scene to see how to setup your scene to render correctly.

Edited by Enivob - Sept. 1, 2017 16:36:25

Using Houdini Indie 20.0
Windows 11 64GB Ryzen 16 core.
nVidia 3050RTX 8BG RAM.


eddgarpv: Member; 64 posts; Joined: July 2005; Offline

Sept. 1, 2017 4:45 p.m.

Smokeless Flame from the Pyro FX doesn't have density. Just take a look at the dop import and smoke object. The pyro shader is using heat as density volume.


coolkalle: Member; 13 posts; Joined: March 2017; Offline

Sept. 14, 2017 7:41 a.m.

I finally got the cache rendering like I wanted. I think the issue was that my cache wasn't storing the parameters I needed to recreate the simulation. What I had done was create a standard Smokeless flames sim and then cached it out using the “Pyro” preset inside of a Dop Import fields node. It seems that the Pyro preset does not export the needed values to render a smokeless flames sim correctly (Assuming you try to render it using a Smokeless flames material)

What I did to fix this was go to my DOP import fields node, and choose the preset “Fire (DSD)” instead. This gave me a cache that I could plug the standard Smokeless flames material into and it rendered out just fine.


rutenio3: Member; 2 posts; Joined: Nov. 2017; Offline

Nov. 29, 2017 3:44 a.m.

coolkalle
I finally got the cache rendering like I wanted. I think the issue was that my cache wasn't storing the parameters I needed to recreate the simulation. What I had done was create a standard Smokeless flames sim and then cached it out using the “Pyro” preset inside of a Dop Import fields node. It seems that the Pyro preset does not export the needed values to render a smokeless flames sim correctly (Assuming you try to render it using a Smokeless flames material)

What I did to fix this was go to my DOP import fields node, and choose the preset “Fire (DSD)” instead. This gave me a cache that I could plug the standard Smokeless flames material into and it rendered out just fine.

Hi! I have the same problem. Can you upload an example file bacause I only see a cube in my render. I marked Fire DSD in my import but i only see the same.
Thx!

https://imgur.com/a/EWmGt [imgur.com]

Edited by rutenio3 - Nov. 29, 2017 04:22:51

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