Fire attributes from voxel birth to dissipation

[GlennimusPrime]

Title is a bit misleading.. I realise Pyro volume simulations don't really have a birth and death point, but what I'm hoping to achieve is to be able to colour or alter the transparency of my fire closer to the base or emission point of the fire.

Currently my fire is looking really nice, apart from the base of the fire where it first emits from. I'd like to make this area more transparent.

I'm using the Redshift volume shader, but unfortunately cannot post a .hip file due to work non disclosure stuff.
I can create a simplified version of the scene if need be.

[ryew]

I'm not a redshift user, so if you're seeking RS shader advice I can't offer suggestions, but any time I've tweaked pyro volumes in post for rendering in the past it has typically been via  a Volume VOP masked/driven by an attribute or volume

[Benyee]

On 2022/8/3 at 5:34 AM, GlennimusPrime said:

Title is a bit misleading.. I realise Pyro volume simulations don't really have a birth and death point, but what I'm hoping to achieve is to be able to colour or alter the transparency of my fire closer to the base or emission point of the fire.

Currently my fire is looking really nice, apart from the base of the fire where it first emits from. I'd like to make this area more transparent.

I'm using the Redshift volume shader, but unfortunately cannot post a .hip file due to work non disclosure stuff.
I can create a simplified version of the scene if need be.

just some tips for you

here I created a field like "age field" to post-modify the dop fields before getting into shading/rendering

OR,simply use height

cheers

post-modify_fire_opacity.hip

 

[GlennimusPrime]

On 8/3/2022 at 11:32 AM, ryew said:

I'm not a redshift user, so if you're seeking RS shader advice I can't offer suggestions, but any time I've tweaked pyro volumes in post for rendering in the past it has typically been via  a Volume VOP masked/driven by an attribute or volume

@ryew this is the process I'd expect to work, I'm just not sure how I'd go about creating those attributes.

Thanks @Benyee thanks for going to the trouble of building an example scene, although I'm afraid it seems corrupt when I open. A few of the nodes have been replaced my merge SOPs, which I think can happen if the file is corrupt - Or possibly the file was created in a newer version of Houdini than what I'm running here (19.0.383) due to needing the Redshift plugin.

 

[Benyee]

9 hours ago, GlennimusPrime said:

Or possibly the file was created in a newer version of Houdini than what I'm running here (19.0.383)

no big deal,it was a h19.5 version,here i updated a new one for h19.0,hope it helps

post-modify_fire_opacity_h19.hip

[GlennimusPrime]

Hi thanks so much @Benyee for outputting this file again.

I can understand the workings behind this now thank you - So it's all about matching the original vel from the fire sim to create the particle trail which in turn passes the masking attribute over to the flame mask. It's quite the workaround, but looks like it's doing what I'm after. Again thank you for this, it'll help me out a lot!