Maya VFX Series: Fire Effect using Bifröst Aero 

Comments like this make my day. Appreciate it

Amazing to hear

Glad to hear you found them useful

Glad I could help 🙏🏼

There is default preset in aiStadardVolume shader for bifrost. It will fill corresponding fields for you. Author types it manually to teach us but you probably would use preset instead until you have a custom parameters inside bifrost. Keep in mind also you might vary parameters. You might apply density instead of temperature and vice versa in emission/transparency/color fields :) You might also scale/remap/clamp them as any other parameters in Maya to get endless artistic results. You ever don't need an fuel/combustion to get a fire. You might use single source of gas and just crank up temperature in aiStandardVolume to reach blackbody's fire range instead of smoke :) Fuel/combustion allows you to get significant "spikes" of temperature in your gas cloud. But you might achieve the same result just adding contrast to your voxel_density values. Think of as it's a fractal noise (because it is :))). You have a ramp (gradient) of values. Density and temperature. It's like grayscale noise pattern. Now you could remap/recolor/level/curve it just like any other ramps. "blackbody" preset in aiVolumeShader is just a color ramp preset according to real physics (black body emission colors). But you might replace it with any custom ramp instead. Kelvin's parameters in aiVolumeShader ARE just "levels" controls for this regular ramp.

Glad you enjoyed it Kishan

Thank you RC

Node graphs are looking confusing and complex at a first glance. But it's very native to our brains. They are _literally_ mind maps :) Once you got it you'll never go back to layers/stacks/lists anymore. That's why NUKE looks much harder to understand for beginners corresponding to AE, but you'll never prefer AE once you meet NUKE/FUSION. The same with Maya. You might work with native Maya particles/fluids in native node graphs (in hyper graph/node editor) but tutorials wouldn't teach you that way. They would probably guide you over outliner and attribute editor what's very non-intuitive. Easier to manage but harder to understand what's going on :) That's why you feel so comfortable when you dive into node graphs (bifrost graphs in that case).

@@SugarTouch I'm working with Houdini now . And i prefer node based work flow like you said.

That is so true Evan. The reality is it never ends. There is always new ways of doing the old things. 🙂

I agree to SARKAMARI :) I'm in Maya for 20 years and still learning each day :) Just imagine what is the level of understanding is in heads of Maya _creators_ if USERS have to spent years to explore this universe :)))

Appreciate the kind words Hamed.

Thanks for your warm feedback

Thank you Akhil

Move the assign shader along with the aiStandardVolume node after the cache node, and plug it into the output

Source air has got the quality (needs to be lowered). Also you can render with no cache but it requires very strong processing power. Check the timestamps for the caching section. :)

@@sarkamari Thanks for the reply. With your help I managed to solve both of my problems. :)

Pixelated (blocked by squares) fluids are mostly caused by your "details" in source and your temperature ranges. Bifrost calculates density/temperature by grids in space. Voxel _cubes_. One temperature/density value inside one cube. aiVolumeShader smoothes and fades these results but they ARE still there. If you crank up your temperature range in aiVolumeShader your density/temperature values jumps above "fade-off" and became visible. If you need brighter flame - don't crank up temperature or density. Rise the emission instead. It will shine brighter accordingly to environment but wouldn't "block" visible flames/fluids. You have to keep in mind that "look" of volumes are not physically realistic. It's just applying incoming density/temperature values to color ramp. It's a fake. Simulation is accurate but visualisation is NOT. :) If you see block it just means the range of temperature in simulation is not significant for your purposes. If you need a candle in front of star you have to simulate physically accurate temperature ranges from 500 to 5kk kelvins (or whatever). Than your visual ramps will work :) Otherwise you have to trick/cheese your image on post by glow/levels/curves/whatever to remap Colors accordingly. Renderer will "fade" your density/brightness of gas from 1 to 0 in your temperature range. If you'll ask him to not fade any temperature/density up to 0.9999 you'll have visible blocks :) You need more variations of temperature in simulation instead. Or more voxels in computation (source details size/fluid size). But it will significantly affect render times. Keep in mind you don't need real flames. You need beautiful believable picture of flames until you work for DARPA. :)

use Tab key

hi Nazim and thank you for the kind words. I share ALL scene files for most of my videos via my Patreon.

Glad i could help

Watch my smoke tutorial

@@sarkamari Can't find the motion streak option in the bifrost graph and I have no idea how to fix the dotted result

Bounding box is dynamic. It stretches to "hug" your simulation. It's not cropping it. The reason you simulation won't expand as you expect mostly comes from fluid itself. It appears there is some sort of clamping by lifetime of particles or density or whatever in parameters of source. Dissipation (endless going up) mentioned here is important too. Or might be the density parameter in your source OR MATERIAL (aiStandard Volume) is not big enough. There IS a gas but you cannot see it because aiStandardVolume's density value making it invisible from particular range. When I facing such problems it's usually density or influence issue. Mostly in aiStandardVolume because bifrost has physically realistic default values until you change it. But your source and your material don't. You must keep in mind bifrost is very sensitive to scene scale. And your source "details" and "scale" params in bifrost are very important. Author might have Maya working in centimetres but your setting are in meters. Not mentioned in tutorial (assuming everything by default I guess).

If you don't see the white cube in the render then there's a big chance that it come from your viewport settings

@@sarkamari , Thank you. Yes, by switching the viewport rendering engine to DirectX 11, everything was displayed normally :)

Hi. I have another one using native fluid sim. Check out my VFX playlist

do you mean native Maya fluids or native bifrost nodes instead of custom noise/random operators ? :)

You don't have to. It's just one way of supporting this channel for the FREE content I provide.

@@sarkamari Thank you. Your tutorial helps me a lot.

Where is now? It got deleted?

Yes Cliff. Scene files are now available on my Patreon page

I believe Bifrost was a seperate download (as a plugin) back in 2019 version. You still can download Bifrost as a plugin from autodesk website but from 2020 it gets installed with Maya. Definately worth a try

@@sarkamari thank you :) i would like to download the updated version but I am using an educational license and graduated in 2020. So I think to update that might mess up my license? bc I have a 3 year license and I heard they are only doing 1 year licenses now. im trying to use maya as much as possible before my license expires though.

Just bring it into another pane by pressing the + then copy/paste.

@@sarkamari Awesome, thank you!

@@sarkamari I'm sorry to ask this, I'm new to maya can you tell how do i import that .mb file into maya. sorry for being so dumb

@@sarkamari whenever i press + it creates a new graph, what do i do after that ?

@@sarkamari Figured it out thank you

The typical way is to middle mouse drag onto an empty area within your bifrost graph

okay thank you

There is "collider" node just like source or influence. And simulate_aero node has input for it (lot of them :). You might even input one simulation result as collider inside next one to achieve inter-fluids collisions (like a fire vaporing your liquids or melting your snow etc :). Keep in mind that when you put objects from scene into bifrost graph you MUST keep in mind scene scale. Bifrost is very sensitive (just like any simulation engine) to "real" size of your objects according to your Maya settings (meters/centimetres) . There's a dedicated attribute in "source" node to scale simulation accordingly. It's not mentioned here because author uses "native" internal primitive sphere as n emitter. Not an object from scene (or input node).

Will do

Yess me too, Could you please tell us how? Or send a link if youve alredy done a video how to do it @SARKAMARI

@@DrBipolar im stuck at the noise operator bit, link doesnt do anything.

Scene files are available on my Patreon page now

It’s available on my Patreon Gold tier

Haha. I hear you. I also have a tutorial on fire using fluid container . :) Make sure to check it out

@@sarkamari I know man. But, I'm trying to learn the newer stuff, the new Maya technologies with a future. Bifrost is so much more efficient, and the bifrost graph kicks ass. Trying to focus my self-education on that.

It's interesting SARKAMARI uses custom operators to modulate parameters of SOURCE but bifrost teams usually expects us to modulate _influence_ instead. There's native modulate_influence node for it. You have to connect it just like any turbulence and dissipation (actually IN turbulence/dissipation). SARKAMARI is trying to tune emitter (source) instead to achieve the same result. Seems like it just adds some clarity into node graph. The general parameters are always at the very ends of the "tree" and not scattered across. But it will force you to use custom "macros" just like we have here :) And you might combine any group of nodes into "operator" anytime (and expand it back and forth). I'm sure noise/random operators ARE groups of native nodes just "grouped" to not "blow your flow" :)

@@SugarTouch Eh.. I think it's important to learn what the base capabilities are before you start looking for scripts that may or may not exist. Don't know if that makes sense. I will go the influence route instead and follow along as closely as I can.

That's so shitty

@@rich797win4 it is if the video depends on it.

@@NanoGameLab The node is not even custom-made. You can find it in the Bifrost browser

@@rich797win4 do you mean the aero_uvw_field_noise?

Yes and the randomize node

you have to do it on the solver level . needless to say initial state cannot be applied to gas but you can do that on the mpm solver type

@@sarkamari can you please do tutorial on this set initial state?

It's easier to cache out bifrost result and import it as Arnold's native volume object. Acts like alembic. You might retime/crop it as you wish later. This is the way to "loop" your simulations too in case you need endless seamless "flaming" or whatever. :)

Have you checked both tabs on the node?

@@sarkamari I'm sorry just now I'm checked I'm using bifrost older version not the 2.1

@@sarkamari I connect out to air source input of the fuel node now it works thanks bro

That explains it. :)

Ask away Damocles

I use 2020.1 and any higher version should work obviously :)

@@sarkamari but i got 2020

@@ady7d77 Bifrost is updated independently and there are updates for any (compatible) Maya versions. Just check bifrost site (from plugin info). Maya versions are not important here. Just like with Arnold render you're updating aside with Maya.

Simply press tab on your keyboard

@@sarkamari When you connect the nodes when you have the simulation at 5:00, when I play the simulation nothing happens :( I have it just like in the video and nothing, what can I do?

Might come from viewport settings. For example make sure your viewport is set to shaded. Double check the output node as well and make sure everything is connected :) let me know how you go

you need to enable the plugin. look into introduction to bifrost aero on my channel

Will you get the same warning if you disconnect the cache node from your graph?

There is a "experimental" unified "file_cache" node in bifrost. It allows you to switch between read/write/bypass states. Try to disconnect file_cache node to be sure. And (just a tip) when you've done with your simulation, just cache it as vdb and use Arnold's volume object (in Arnold's menu) to load it as static reference. Hide your bifrost in Maya to skip it from counting until you need to change something later. It's much easier to work with "baked" volumes instead of utilising whole bifrost tree/engine all the time :) Assign the same material to it.

My gear is actually relatively old. I have two xeon e5, 64 GB DDR3 and Quadro k5000,Tesla hybrid. Still plowing through but time make some changes

@@sarkamari I would like to see how threadripper deal with bifrost.

Do you mean aiStandardVolume ? You probably mistyped parameters like volume_dencity or temperature etc. There's a ready preset in aiVolumeShared for bifrost. It will put default parameter names in corresponding fields for you. Author types them manually to learn us what's going on :))) But usually you wouldn't do it until you have tons of custom properties inside bifrost :)

You can download the scene, Amit. The link is in the description :)

👍👍 thxx

@@sarkamari Where is that link, I can't see it in the description ):