Hello everyone.

I've been using Houdini for about two years now and have been greatly enjoying it. However, I seem to have hit a brick wall awhile ago that I just can't seem to get past. Primarily, in effects department.

Right now, I'm attempting for the second time to wrap my head around the Pyro solver, but I just cant seem to make any real progress. I've viewed and worked along with every tutorial I could find about the subject matter, but the second I try anything on my own it just… turns into a complete mess. I'm trying to start out with very simple things(such as a torch or pan fire)but for the life of me I just cannot shape the fire correctly or make it look anything like my references. I've studied each parameter and have developed a basic understanding of what each does. The general workflow and the process of putting all of this information together seems to be whats giving me the most trouble. Right now I don't feel like I'm improving at all, and simply spending more and more time on it doesn't seem to really be doing anything.

I understand that truly grasping this kind of thing takes a long time and I don't expect to become a master overnight. The main thing is that I just don't feel like I'm really making any progress at all or getting any better. It's like I'm missing something vital.

So, I guess my question is, for to those of you have developed an understanding for the Pyro solver,fire effects or really even effects in general, how did you start out learning? What did you do if you felt stuck? Is there any general advise that you can to a noob like me who has trouble seeing the forest for the trees?

Thank you very much for any help that you can give me.

I know how you feel. I have been stuck for weeks on my current pyro simulation. Every day is the same thing. I get up I run sims all day and try to dial it in by changing one parameter at a time. So it is not unusual to try and try again.

The best advice I can give is to turn off or turn down a lot of the parameters and increase them one at a time to observe their effects. If you have not watched Peter Quint's tutorial series on the pyro combustion model it is worth checking out, even though it is 5 years old.

My aha moment came when I realized you need to actually supply an attribute before the fluidvolume create. An attribute such as @fuel or @temperature. Otherwise the shelf tool just creates a default to get you going and links them both together.

There is also a fairly major bug, IMHO, in the H16 Disturb functionality of the pyro solver itself. It treats the vel field as a float, at the VOP level, when it should be treating it as a vector. This means if you are supplying velocity data in the XYZ direction only the X is being used to alter density. You can, of course, unlock the pyro solver and dive into the GasDisturb and change the parameter from Float to Vector to fix this.

I guess my advice is to keep your simulation length short while developing, like 120-192 frames. This allows for quicker turn around. Work at modest division sizes, I use 0.1 while developing during the day and I set it a little lower for my overnight sim. Yep, always setup an overnight simulation or render. It is like getting a free one-off.

Also post your HIP file on a thread on this form or OdForum. People are more likley to help if they can pull down your WIP and have a look. It is easier to dial in advice when you can see the node setup a person is using.

Thank you very much for the advice and all of the information!I took another look at Peter Quint's videos and they were very helpful!

Unfortunately I still don't think I'm any closer to achieving the look that I want. Sometimes I feel like I'm getting close… but as soon as I start lowering the division size on my fire it comes out looking weird and often kind of stringy.

I've included a file of one of my many attempts. I tried to stay as simple as I possible could.

Also, This is kind of the look that I'm going for right now.

https://youtu.be/pEVl8R9Q9EM [youtu.be]

I'm not trying to create a fire ball or anything explosive like that yet, just a pan of flaming grease.

Thank you again for the help and to anyone who can help me figure this out!

Those kinds of animations really need some play with the numbers time. Here are some tweaks I made to your scene. I added vel to the resize field so the container will grow in size when velocity gets larger. I also increased the buoyancy so the flame/smoke will rise quicker. I also increased the Wind Tunnel value on the Y direction to encourage even more rise. I also lowered the cooling rate and increased flame height. I tweaked the Dissipation curve for smoother fade out. To control the overall action I animated the Source Volume value, from 0 to 1 to create a quick flare up, then animated it back down quickly. You could do this a few times for multiple flare ups. I linked the temperature field to the density field in the same node so temperature rises and falls with the animation. Oh yeah, I also enabled curl noise for the velocity field on the source node.

Simulation is only half of it, however, the other half is rendering so you can pick up some look refinement there.

Awesome! Again, thank you so much for the help! Ill be sure to work around with what you gave me.

There's something else that I've been kind of wondering lately. Is this type of effect not a good idea for someone like me who is newish to pyro? I seem to have a bad habit of judging how difficult certain effects are to create when I'm just starting out.

This seems like a reasonable effect to start off with. Any kind of effect that is just one element is a good place to start. I would not include other interactions with flames or fluid as a beginner.

Just keep making stuff!

After watching that Youtube video I used your hip file and changed several things to my liking. All nodes I added I colored red. I added my own dopnet because I just like to start from scratch. You would be amazed as to how simple it is to get a very basic “pan on fire” simulation up and running. Check out the attached hip file.

My take on basic pyro look development:

Work on the overall look of the fire. I usually start on the combustion tab, then move on to the simulation tab to tweak things like how high flames shoot up by changing the temperature diffusion and then adjust the cooling rate accordingly. Only when I am happy with the overall look I then move on to the microsolvers (shape tab).
I noticed you used shredding in your sim. I would advice against using shredding for the specific look you are after. I turned it off in my sim and turned on sharpness. Sharpness get's you more wispy/streaking flames.

Smartest advice I can give you is to keep experimenting!

Just do the Applied Houdini tutorials - most of the advice here seems straight lifted from it.

http://www.appliedhoudini.com/#/volumes-complete/ [www.appliedhoudini.com]

aRtye
Just do the Applied Houdini tutorials - most of the advice here seems straight lifted from it.

http://www.appliedhoudini.com/#/volumes-complete/ [www.appliedhoudini.com]

aRyte, it seems like you are a tiny bit prejudiced. Stephen Knipling's tuts show a completely different pyro effect. But I do agree, check out any and all tutorials from Stephen. In fact, watch any tutorials you can find on the subject.