Billowy Smoke Color According To Age/Life

[dtarr77]

Hi,

 

I am trying to create an effect where my smoke changes color depending on its age or lifespan like particles rather than temperature.  My experience in Houdini is still pretty amateur and I have not found any way of doing this in my internet searches so far.  I found one that mentioned using pcfilter and transferring particle age over to the smoke volume without much explanation.   Unfortunately, I have never used point cloud filter and have no idea where to even begin to go down that route.  I have played around trying to figure it out myself but have had no luck.  I know this is an awesome Houdini forum community so I figured I'd see if anyone here might be able to offer some insight or help on this matter.

 

Does anyone have any suggestions on possible routes to achieve this effect?  OR  Do you know how using the pcfilter as stated above might work?

 

I have particles in the project that are using the effect I want to create with my smoke where they go from pink-ish to a light blue.  So I have included a picture below that maybe will help explain better what I am looking for.  Any help/advice you guys are able to provide will be much appreciated.  Thanks.

[Atom]

What about something like this...

 

Copy a sphere onto the particle points and scale them by age.

Then create a fog volume out of that surface geometry, this becomes the density value for the shader.

Next create a new volume from that same geometry and name it temperature.

From the original points rename the age attribute to temperature.

Now that you have a matching volume name and attribute name you can use a VolumeFromAttribute node to create the temperature field.

Merge the density and temperature volumes together and you have output that the BillowySmoke shader can make use of.

 

You may need to increase the resolution on the volumes to get a cleaner render.

ap_particle_age_to_temperature.hipnc

Edited February 7, 2016 by Atom

[dtarr77]

Thanks for replying Atom, I appreciate it. I will check your file out and try your process in my project file and let you know how it turns out. Thanks again.

[dtarr77]

Hey Atom,

 

Again, I appreciate the help.  I went through the file and got it to work, but is not exactly the route I am looking for.  Although it is still a very useful lesson I didn't know on creating attributes in volumes and such.  So it is still a helpful file I will keep to refer to as I continue learning Houdini.

 

What I probably should have stated in my first post to make it more clear on what I am aiming for is that I have a pyrosolver already working.  The smoke is being emitted from a different set of particles (image01 below)

 

 

and I want to implement age into that smoke. (image 02) 

 

 

That way I can create a similar color effect to the particles in the image of the first post.