Phoenix FD Flamethrower Problem

[chadstevens]

Hi guys and girls,

I'm having a problem getting the same results as this flamethrower tutorial on the ChaosGroup page.
Link: https://www.youtube.com/watch?v=LY8cL9caGRg

Things you should know:

01. I'm using the latest nightly for 3ds max 2017 (I have also tested it in 2016 with no success)
02. units are setup the same as in the video, in cm for both the display units and the system units.

I must have followed the tutorial about 5 or 6 times now from start to finish to make sure I did not miss anything, but I get nowhere near the same results. I don't know if this method is old and if there is a better way of doing it, but that is why I'm posting it here.

Several differences I noticed between the nightly and the version Tsvetan is using in the tutorial video.

01. Massive Vorticity is not there so I disabled it and used Classic Vorticity (tried both, neither worked.)

02. Conservation method is called Direct Symmetric, whereas in his video it's just called symmetric (I tried all of the methods, none worked.)

03. In the Pheonix source there is no checkbox for "use particle size" but there is an option called use particle shape (I tried all the options in this drop-down box, only two of them actually simulated anything, but alas none of them worked.)

Also note that he changes the values throughout the video so the values that I have in the file I have attached are from the last part of the video. Throughout the video my simulation never looked like his.

I'm really stumped and this is for a live job that I need to get a similar results for.
Here: http://image.slidesharecdn.com/1-1in...?cb=1355391074

I'm sorry for the long message but any help would be greatly appreciated.




Phoenix FD Nightly problem.zip

[georgi.zhekov]

Hello,

As the video was made 2 years ago, a lot of things in Phoenix have changed.
Using the same settings will produce different result than what was before as some things were rewritten in order to produce better results.

The Fuel component now is behaving a bit differently and probably that's the case you're getting different results.
Unfortunately it is broken in the nightlies and you won't be able to get good result for now, but we're aware of the problem and we're on it. I hope we will fix it soon.

As for the Phoenix Source the "use particle shape" option is the old one "use particle size", but now you don't need to set a shape for the particles at all in PFlow - just set the option to custom size and dial the value in there - it should behave the same way.

[chadstevens]

Hi Georgi, thanks for your reply

You said "As for the Phoenix Source the "use particle shape" option is the old one "use particle size", but now you don't need to set a shape for the particles at all in PFlow - just set the option to custom size and dial the value in there - it should behave the same way."

Are you saying I should just set the option in particle shape to "Sphere, 1 voxel" (the default) in the source rollout? and not use spheres to emit them from the particle flow?

If the fuel is not working properly would you suggest that I download the official phoenix FD 2.2 build or is there another nightly that I can use that the fuel parameter is working in?

Also you say that a lot has changed since the video, so is there an easier more efficient way to do this now, if so, could you point me in the right direction to achieve the result in the video or the image that I had linked?

If anything that I have asked is unclear please let me know.

Thanks very much.

[georgi.zhekov]

In the source if you set the size for the particles to "Sphere, custom size" and set it to 2.4 it will be exactly as in the scene you have provided. Phoenix will assume a sphere with 2.4 radius for each particle - there is no need to attach shape node to your PFlow.

If you download the Official 2.2 build - your result should be really close to what you see in the tutorial. If that works for your case - feel free to do that.

Unfortunately the fuel bug won't let you get the desired result with the nightlies but when we fix it all should be good - I will let you know when we have a fix for that.

The way of building the scene as shown in the video is still relevant - it's just that the behavior of some of the parameters has changed and using the same settings will produce different result.

When we have the fix I will get you sample scene.

Best regards,

[chadstevens]

Thanks for the info, I went back to 2.2 and everything worked perfectly.

Cheers

[Svetlin.Nikolov]

Hello,

Something I noticed in your scene that you might want to watch out for is that the PHXSource's Time Base option is set to 'Particle Age' instead of 'Absolute' - this way when you animate a value on the source, it will apply to each separate particle depending on the particle's age - e.g. if you animate the discharge down to zero at frame 30, this means that each particle will emit for 30 frames since it was born, so unless you turn off particle birth, there will always be fire produced by the particles.

Also, turns out that the bug Georgi was referring to was a false alarm, so the burning really should work okay in the builds you tried.

Note that there were several changes since the official 2.2 version:
- Now smoke will be produced only in those voxels where there is more fuel than oxygen. Oxygen is what is left after subtracting from 1 the fuel and the smoke values.
- There are a couple of new controls for controlling how fast the fuel burns out - "Fuel Depletion", and how much smoke is produced - "Smoke Amount".

For your scene to look closer to the tutorial, I would turn the source's Time Base to 'Absolute' and would bump the Energy up and also reduce the Smoke Amount. I'd also increase the vorticity. It's up to you to experiment with settings and find what looks best

Cheers!

[chadstevens]

Thanks very much for the description, I'll definitely give it a shot.

Cheers.