ANR Tools

ANR Blood Mist 3D

Fine blood mist and spray in 3D: tiny droplets slowed by the air, with a soft haze, from its own nozzle, a matte, or the fast liquid of Blood Sim 3D.

In Nuke: NodesANRSimulationsANR Blood Mist 3D

Overview

Blood Mist 3D adds the part of a gunshot or impact that a liquid simulation cannot show: a cloud of droplets a fraction of a millimetre across that leave fast, are stopped by the air within centimetres, then drift and sink. A soft haze fills the dense parts. Three presets start you off: Gunshot mist, Back-spatter puff and Fine drift.

The mist can come from its own nozzle (placed like the Blood Sim's, with Source XY, Source depth and the camera), from the alpha of a matte on Source, and from ANR Blood Sim 3D on Particles: liquid moving faster than Speed threshold sheds mist along its path, so the mist follows the hit. Use both together, or set Emitter to Off for mist from the Blood Sim only.

Each droplet's path is worked out exactly from its launch, drag and gravity, so any frame renders directly: there is no simulation to run and no cache to build. Look and Physics edits never rebuild the droplets. The mist is lit like Blood Mesh 3D, with a skylight by default or a lat-long HDRI on Environment.

In a blood setup, the Blood Sim feeds both Blood Mesh 3D (the liquid) and Blood Mist 3D (the mist): merge the mist over the mesh and the plate. With a Blood Sim on Particles, the mist uses its camera, Time scale and Scene scale, and hides behind its collision surface.

Inputs

SourceCameraParticlesEnvironmentBlood Mist 3DOutput
  1. Sourceoptional

    Optional. A matte to emit from: with Emitter on Automatic or Source alpha, droplets are born on its alpha, placed through the reference camera at Source depth.

  2. Cameraoptional

    Optional. Your shot camera (a classic perspective Camera): it places Source XY and the Source alpha at the Reference frame, and the mist is rendered through it. Use the same camera as the Blood Sim. Without one, the Blood Sim's camera is used, or else the built-in view.

  3. Particlesoptional

    Optional. ANR Blood Sim 3D, live or reading its cache, connected directly. Its fast liquid sheds mist, and the mist takes its camera, clock and scene scale.

  4. Environmentoptional

    Optional lat-long HDRI, used as the sky in the Skylight lighting modes.

Output. Premultiplied RGBA of the mist at the project format. Merge it over the plate, and over Blood Mesh 3D's liquid.

Quick start

  1. Select your ANR Blood Sim 3D and add ANR Blood Mist 3D. It connects to Particles, copies the Sim's Start frame, source placement, direction, floor and gravity, and connects the Sim's camera.
  2. Choose a Preset: Gunshot mist for an exit wound, Back-spatter puff for a short puff back towards the shooter, Fine drift for a fine, hanging aerosol.
  3. Set Quality to Preview and play the impact. Put the Blood Sim on Read cache for fast scrubbing.
  4. Adjust the amount with Impact amount (own nozzle) and Mist per fast particle (from the Blood Sim), and the look with Density, Haze amount and Mist colour.
  5. Set Quality back to Render and merge the mist over Blood Mesh 3D and the plate.
  6. To use it without a Blood Sim, place Source XY on the wound (or connect a matte to Source), set Start frame to the impact frame and aim with Direction X/Y/Z.

The panel

The node's panel as Nuke shows it, with the values of a new node. Click any control to see what it does; tabs and sections work as in Nuke.

ANR_Blood_Mist_3D1

Bullet Time, the preset, start frame, seed, quality, time and scene scale, and the info line.

Bullet TimeFreeze at1
PresetGunshot mist
Start frame1
Seed1
QualityRender
Time scale1
Scene scale (cm per unit)10
Refresh info
InfoNo frame rendered yet. View a frame, then refresh.

All controls

Setup10 controls

Bullet Time, the preset, start frame, seed, quality, time and scene scale, and the info line.

Bullet TimeCheckboxbulletTime

Freezes the mist at the Freeze at frame. The camera and the look keep following the timeline. Holding a frame costs no simulation time. Ticking it freezes at the current frame. Animate it off to let the mist go on. Freeze the Blood Sim on Particles at the same frame.

Default: off

Freeze atSliderbulletFrame

The frame Bullet Time holds. Before it the mist plays normally; from it on it stays still. Animatable.

Default: 1

Preset

PresetMenupreset

Sets emission, droplets, physics, From Blood Sim and the mist's look; keeps placement, Start frame, seed, floor, gravity and lighting.

Default: Gunshot mistOptions: Gunshot mist Back-spatter puff Fine drift

Timing & quality

Start frameSliderstart

Frame of the impact (match the Blood Sim's Start frame). Nothing is emitted before it.

Default: 1

SeedSliderseed

Picks other droplets.

Default: 1

QualityMenuquality

Preview: at most 640 px, a coarser haze grid and at most 2 blur segments per droplet. Render: full resolution.

Default: RenderOptions: Preview Render

Time and scene scale (with a Blood Sim on Particles: the Sim's)

Time scaleSlidertimeScale

Simulated seconds per frame = Time scale / frame rate, as Blood Sim's: 1 is real time, .25 is 4x slow motion, 2 twice as fast. Used without Particles; with ANR Blood Sim 3D on Particles the mist follows the Sim's Time scale.

Default: 1

Scene scale (cm per unit)SlidersceneScale

Centimetres per world unit of your scene, as Blood Sim's: 10 is the presets' scale, 1 a centimetre scene, 100 metres. Speeds, Nozzle and Birth radius, Droplet size, Gravity, Wind, Turbulence, Haze size and the Speed threshold keep their values at the 10 cm reference and are converted for you; placement and the floor are in your scene's units. Used without Particles; with ANR Blood Sim 3D on Particles the mist follows the Sim's.

Default: 10

Info

Refresh infoButtonrefreshInfo

Show the droplet counts, whether births were reused, and the render times of the last rendered frame.

InfoStatusinfo

The info line filled by Refresh info: droplet counts from the emitter and from the Blood Sim, whether they were reused, the render time, and any time or scene scale in use.

Source16 controls

The mist's own emitter: placement, launch and amount.

Emitter

EmitterMenuemitter

Automatic: the Source alpha when Source is connected, else the point nozzle. Off: mist only from Blood Sim.

Default: AutomaticOptions: Automatic Point nozzle Source alpha Off

Source XYPositionsourcePoint

Nozzle position in the reference camera, as Blood Sim's Source XY. Source alpha emission ignores it.

Default: 1024 855.8

Source depthSlidersourceDepth

Depth behind the reference image plane, as in Blood Sim. Source XY stays aligned in the reference camera.

Default: 0

Camera distanceSlidercameraDistance

With a Camera connected: the reference image plane's distance from it (Blood Sim's Camera distance).

Default: 10

Reference frameSliderreferenceFrame

With a Camera connected: the frame whose camera places Source XY and the Source alpha in world space.

Default: 1

Launch

Direction XSliderdirectionX

World launch direction. The default is Blood Sim's Gun hit direction: sideways and towards the camera.

Default: 0.8

Direction YSliderdirectionY

World launch direction.

Default: 0.35

Direction ZSliderdirectionZ

World launch direction.

Default: 0.5

Spray angleSliderspread

Cone half angle in degrees.

Default: 35

SpeedSliderspeed

Median launch speed, world units per second (40 = 4 m/s). Drag stops the droplets within a few centimetres.

Default: 40

Speed variationSliderspeedVariation

Log-normal spread of launch speeds: many slow droplets and a few very fast ones. 0 = all at Speed.

Default: 0.6

Nozzle radiusSliderradius

Radius of the emitting disc, world units (.05 = 5 mm).

Default: 0.05

Amount

Impact amountSliderburst

Droplets in the impact.

Default: 600000

Impact durationSliderburstDuration

Seconds over which the impact is emitted; most droplets leave in its first quarter.

Default: 0.03

Flow rateSliderrate

Continuous droplets per second after Start frame (a wound that keeps misting). 0 = impact only.

Default: 0

Flow durationSliderrateDuration

Seconds of continuous emission after Start frame.

Default: 0.5

From Blood Sim10 controls

Mist shed by fast liquid from the Blood Sim on Particles, and the collider holdout.

Spawning

Mist from Blood SimCheckboxfromLiquid

With ANR Blood Sim 3D on the Particles input, fast liquid sheds mist along its path.

Default: on

Speed thresholdSliderliquidThreshold

Liquid slower than this (world units/s; 8 = 0.8 m/s) sheds no mist: pools, drips and slow streams stay clean.

Default: 8

Mist per fast particleSliderliquidRate

Droplets per second each liquid particle sheds per unit/s it moves above the threshold.

Default: 60

Spawn windowSliderliquidWindow

Only liquid within this many seconds after Start frame sheds mist: the impact, not the drops falling later. 0 = every frame.

Default: 0.1

Max per frameSliderliquidMax

Most droplets one Blood Sim frame may shed; above it every particle sheds proportionally less.

Default: 200000

Launch

Inherit velocitySliderliquidInherit

Share of the liquid particle's velocity the mist leaves with.

Default: 1

SpreadSliderliquidSpread

Cone half angle around the liquid's direction, degrees.

Default: 20

Mist speed variationSliderliquidSpeedVariation

Log-normal spread of the inherited speed.

Default: 0.35

Birth radiusSliderliquidRadius

Droplets are born this far around the liquid particle's path, world units.

Default: 0.01

Holdout

Collider holdoutCheckboxholdout

Hide mist behind the Blood Sim's collision surface (the collider in its particle data).

Default: on

Physics20 controls

Droplet size and lifetime, air drag, gravity, wind, turbulence and the floor.

Droplets

Droplet sizeSliderdropletSize

Median droplet diameter, world units (.001 = 0.1 mm at 1 unit = 10 cm). Sets each droplet's cross-section; drag follows Drag.

Default: 0.001

Size variationSlidersizeVariation

Log-normal spread of droplet diameters. Small droplets stop sooner and sink slower.

Default: 0.5

LifetimeSliderlifetime

Seconds a droplet stays visible; it fades out over the last Fade out share of it.

Default: 0.9

Lifetime variationSliderlifeVariation

Lifetime x (1 +- this), uniform.

Default: 0.4

Fade outSliderfadeOut

Share of each droplet's life over which it fades out.

Default: 0.3

Air

DragSliderdrag

Air drag of a median droplet, 1/s: it loses 63% of its speed relative to the air in 1/Drag seconds and sinks at Gravity/Drag. 40 fits a 0.1 mm blood droplet (terminal speed 25 cm/s).

Default: 40

Drag size exponentSliderdragExponent

Drag of each droplet = Drag x (median size / its size)^this. 2 is Stokes; 1.5 fits measured terminal speeds of 0.05-0.5 mm drops.

Default: 1.5

Gravity XSlidergravityX

World acceleration, units/s^2 (Blood Sim's presets: -98.1 in Y).

Default: 0

Gravity YSlidergravityY

World acceleration, units/s^2.

Default: -98.1

Gravity ZSlidergravityZ

World acceleration, units/s^2.

Default: 0

Wind XSliderwindX

Air velocity the droplets drift with, units/s.

Default: 0

Wind YSliderwindY

Air velocity the droplets drift with, units/s.

Default: 0

Wind ZSliderwindZ

Air velocity the droplets drift with, units/s.

Default: 0

Turbulence

TurbulenceSliderturbulence

RMS swirl displacement of a slowed droplet, world units. Fresh fast droplets fly straight; slowed ones drift and curl. 0 = off.

Default: 0.08

Turbulence sizeSliderturbulenceSize

Swirl size, world units.

Default: 0.25

Turbulence evolutionSliderturbulenceEvolution

Pattern changes per second.

Default: 1.5

Turbulence seedSliderturbulenceSeed

Picks another swirl pattern.

Default: 1

Floor

FloorCheckboxfloor

Droplets stop on the floor and fade.

Default: on

Floor heightSliderfloorY

Droplets reaching it stop and fade (Blood Sim's default floor).

Default: -2.2

Floor fadeSliderfloorFade

Seconds a landed droplet takes to fade out.

Default: 0.08

Look26 controls

Mist colour and density, scattering, haze, motion blur and lighting.

Mist

Mist colourColourmistColor

Single-scattering albedo of the droplets: blood passes red and absorbs green and blue.

Default: 0.75 0.0549999997 0.04500000179

BrightnessSliderbrightness

Multiplies the light the mist scatters; opacity is unchanged.

Default: 1

DensitySliderdensity

Multiplies every droplet's cross-section (1 = physical: pi r^2 per droplet). Opacity grows with it.

Default: 1

Forward scatteringSlideranisotropy

Henyey-Greenstein g: how strongly droplets scatter light forwards. Backlit mist glows; front-lit mist stays dark red.

Default: 0.7

SparkleSlidersparkle

Per-droplet brightness variation (fine speckle).

Default: 0.6

Self shadowSliderselfShadow

How much the cloud shadows itself from the key light and the sky. 0 = off.

Default: 1

Speckle sizeSliderminFootprint

Smallest droplet footprint, pixels (Gaussian sigma). Sub-pixel droplets keep their optical depth and give fine speckle.

Default: 0.6

Haze

Haze amountSliderhaze

Adds a soft haze where the droplets are dense (the unresolved finer aerosol): this x the droplet extinction, blurred over Haze size. 0 = droplets only.

Default: 0.4

Haze sizeSliderhazeSize

Blur radius of the haze, world units.

Default: 0.15

Motion blur

Motion blurCheckboxmotionBlur

Streak droplets over the shutter.

Default: on

ShutterSlidershutter

Exposure in frames, centred on the frame (0.5 = 180 degrees). Droplets streak along their closed-form paths.

Default: 0.5

Light

LightingMenulighting

Skylight: the studio sky (or the Environment input) through the droplets' phase function, with the key softbox. Skylight + key: plus the directional key. Key only: the key light and Ambient fill.

Default: SkylightOptions: Skylight Skylight + key Key only

Sky intensitySliderskyIntensity

Scales the whole sky, the Environment input included.

Default: 1

Sky rotationSliderskyRotation

Turns the sky, the Environment input and both softboxes about the world up axis, in degrees.

Default: 0

Ambient fillSliderambient

Flat fill light on the mist in every mode.

Default: 0.05

Key lightSliderkey

Directional key light intensity (Skylight + key and Key only).

Default: 1.3

Light XSliderlightX

World direction towards the key light; with the studio sky also where the key softbox sits.

Default: -0.4

Light YSliderlightY

World direction towards the key light; with the studio sky also where the key softbox sits.

Default: 0.8

Light ZSliderlightZ

World direction towards the key light; with the studio sky also where the key softbox sits.

Default: 1

Studio sky (when no Environment is connected)

Sky zenithColourskyZenith

Studio sky colour straight up (Blood Mesh 3D's). Used without an Environment.

Default: 0.02999999933 0.03200000152 0.03500000015

Sky horizonColourskyHorizon

Studio sky colour at the horizon. Used without an Environment.

Default: 0.09000000358 0.08500000089 0.07999999821

GroundColourskyGround

Studio colour below the horizon. Used without an Environment.

Default: 0.0120000001 0.009999999776 0.00800000038

SoftboxSlidersoftbox

Brightness of the studio sky's key softbox, in the Light direction. Mist in front of it glows (forward scattering).

Default: 45

Softbox sizeSlidersoftboxSize

Angular radius of both softboxes, degrees.

Default: 4

Rim softboxSliderrimSoftbox

Brightness of the studio sky's rim softbox (opposite the key, Rim height up).

Default: 40

Rim heightSliderrimHeight

Height of the rim softbox above the horizon, degrees.

Default: 35

Tips

  • Refresh info shows the droplet counts, whether the births were reused and the render time of the last frame.
  • Backlit mist glows, front-lit mist stays dark red: place the key with Light X/Y/Z, or turn Sky rotation so the bright side of the sky is behind the mist.
  • Spawn window limits the shedding to the impact. Raise it and falling drops mist as well, which rarely looks real.
  • Drag sets how quickly droplets stop and how slowly they sink; small droplets stop sooner. Wind makes the cloud drift.
  • Speckle size sets the finest grain of the mist in pixels, and Sparkle varies the droplets' brightness.
  • Set Haze amount to 0 for droplets only, or raise it for a thicker cloud.
  • For Bullet Time, freeze the Blood Sim on Particles at the same Freeze at frame as the mist.

Good to know

  • Needs an NVIDIA GPU, Turing generation (RTX 20 series) or newer.
  • With a Blood Sim on Particles, Time scale and Scene scale (cm per unit) follow the Sim's and are greyed out here.
  • If the Blood Sim has a Camera and the mist's Camera input is empty, the mist's own emitter lands away from the wound and the node warns: connect the same camera, or set Emitter to Off.
  • Connected by hand, the mist keeps its own Start frame, Floor height and gravity: match them to the Blood Sim. Its floor starts at -2.2, while a new Blood Sim's floor is at 0.
  • Each frame reads the Blood Sim frames inside the spawn window. With a live Sim, an earlier frame makes it simulate again from its Start frame: use its Read cache.
  • With Source alpha, a long continuous flow gets slower each frame, because every frame reads the matte from the Start frame on. Keep long Source alpha flows short, or render them to disk.
  • Emission and droplet settings are read at the Start frame; Source XY, depth and direction follow their animation through the emission, and Physics and Look apply at every frame.
  • A mist nobody is viewing frees its GPU memory by itself after about 10 minutes, or after a minute when the GPU is nearly full.

Something unclear or missing? Write to [email protected].