Afterburner jet flame

[crimea]

I've read through a couple threads regarding this, but I can't get a very nice looking typical afterburner flame. It looks too cone-shaped towards the top, unlike my reference which is this:

https://i.imgur.com/CD3SVod.jpg

Below is my setup.

Any tips on how to maintain a more straight and directional flame? Thanks!

[georgi.zhekov]

Hey,

Check the attached scene.

Cheers,

[catche]

Hi, OP here. Thanks a lot for the scene, the image looks great! I'll be able to check it out tomorrow.

In addition to just receiving the scene, it would be great to hear some more info, regarding what I've done wrong and how one should approach these types of things, or any other feedback really. I'd really like to learn how to do these things myself. Looking at the scene will help for sure, but it would be nice to know the thought process behind how you got there.

Thanks.

[Svetlin.Nikolov]

Sure, so most importantly you need many steps per frame in order to get the smooth result (check this section for more info: https://docs.chaosgroup.com/pages/vi...imulationwork?).

You must not have a lot of vorticity, and also the setup uses forward transfer advection which is good when there is fluid ejected from a source and needs to preserve the fluid amount well. Forward transfer advection also produces a smoother fluid than Multi-Pass advection, which aims to add more swirls and detail to fluid effects.

Hope this helps, cheers!

[crimea]

I think the screen shot in OP shows most of the settings just as you describe, so is probably something else. Thanks though.

Regarding the file you shared, I can't get it to render, just renders black. Not sure if it's the simulation that isn't working properly, or render settings. I'm on phoenix v3.04.00 and vray 3.60.02. Simulation files are taking around 7mb.

This is what my phoenix looks like, in case anything has switched due to old version or something: https://i.imgur.com/vXImMln.png

[Svetlin.Nikolov]

Update your Phoenix, we're on version 3.12 now. 3.04 is year and a half old already...

[Svetlin.Nikolov]

Regarding settings and the cone shape, for this effect you don't need a lot of conservation quality - just the opposite. Also - you can't get a jet if you are using Volume Brush - you need Surface Force.

Cheers!

[crimea]

Updating is not up to me. And since last time we tried to upgrade (both phoenix and vray), rendering full ocean mode became much much worse, we are probably not going to upgrade unless it's fixed or there are other improvements (really a downgrade - we tried for 6 months to live with it but it was just not possible). Don't mean to sound too negative and whiny, sorry if I do, just trying to be straight.

So in the file you sent, you don't know what settings could have been messed up for me? I'll try to apply what you've given me now, thanks!

[Svetlin.Nikolov]

My best guess for why your scene is not working well is in the post above - brush mode, and very likely - conservation quality.

Could you be more specific about the ocean issues you are having? You can check the changelogs of Phoenix versions here in order to know what has been fixed in each new version: https://docs.chaosgroup.com/display/...on+Change+Logs

[crimea]

I meant regarding settings in the file that Georgi shared.

Regarding the ocean issues, it's detailed here:

https://forums.chaosgroup.com/forum/...-usage-in-2017

[Svetlin.Nikolov]

Yes, the settings from Georgi's scene are very much the same as the ones in your scene, except for the brush and conservation.

Are there any remaining issue from the ocean thread? You didn't follow up on it so I thought it was okay on your side. Please check 3.12 and let me know if there are any issues there.

Cheers!

[crimea]

Yes I realized I did not explain well enough when I re-read it now. The picture I posted with the nightly shows that there's still a heavy RAM requirement and also long rendering times, but maybe the trick is just to go lower on the ocean subdivs, I don't remember if I tried this or not.

[Svetlin.Nikolov]

Yup, you just gotta keep in mind that the ocean subdivs option means something else between early Phoenix 3 versions and later ones - the polygon count you are gonna get with the same value differs a lot, so the same scene will require different amounts of ram and the more ram it uses, the more detail it will have. So if you were able to get a certain level of detail with, say, 20 gigs of ram, by adjusting the ocean subdivs in newer version you should get the same detail with the same gigs of ram, but just with a different value for the ocean subdivs.

[crimea]

Right, thanks. Will maybe give the newest version a go some time then!

Regarding the flame, after trying and failing, and then investigating the shared scene, another thing I believe makes a difference is setting the source object to be a solid object in phoenix properties, which is default. This was off for mine however, possibly the original scene that was made in a slightly older phoenix didn't have this option? Oh well. Will see tomorrow how it looks. Thank you for your rapid responses.

[Svetlin.Nikolov]

Ah, yes - when you set the Source into volume brush mode, it asks about making the geometry from Solid to Non-solid, so that it could use its inner volume - maybe this is what happened. This will surely change the behavior as well, because making it non-solid would allow the air to pass right through the emitter object while it blows the jet in one direction.