Nodes · 3D
VolumeShade
3Dv1app
Overview
The volume LOOK, separate from the read so one look feeds several VDBReads: density scale, scatter colour, anisotropy (forward/back scattering), emission (fire), self-shadow strength. Without one, VDBRead shows neutral grey smoke.
How to
How-to
- Name the
targets(VDBRead prims); setdensity,scattercolour,anisotropy. emissionandemission_intensityfor fire;shadow_densityfor how dark it self-shadows.- One look can feed several reads.
Inputs
| Input | What it takes |
|---|---|
| in | the image this node works on |
Outputs
| Output | Type |
|---|---|
| out | Scene |
Parameters
| Parameter | Type | Default | What it does |
|---|---|---|---|
| targets | Text | Which prim paths this affects — space or comma separated, * matches one segment, ** any run. Empty = everything upstream. | |
| density | Float | 1.0 | A gain on the volume's density grid: under 1 thins the smoke, over 1 thickens it. |
| scatter | Color | [0.7, 0.7, 0.7, 1.0] | The colour the volume scatters — its albedo. Grey-white for smoke, warm for dust. |
| extinction_tint | Color | [1.0, 1.0, 1.0, 1.0] | Chromatic extinction: which channels the volume stops more. Its extinction per channel is the density times this, normalised to a mean of 1 — so (1, 1, 1) is grey and how much stays the density's business. Stop blue more than red (0.8, 1, 1.25) and a fire seen through the smoke goes red, as soot reddens a fire; light scattered through it reddens the same way. Coverage follows the density alone. |
| anisotropy | Float | 0.0 | Henyey–Greenstein phase: 0 scatters evenly, positive forward (a backlit volume glows at its rim), negative back. |
| emission | Color | [0.0, 0.0, 0.0, 1.0] | The colour the volume emits on its own — fire, a glowing gas — scaled by emission_intensity. |
| emission_intensity | Float | 1.0 | A gain on the emission. |
| shadow_density | Float | 1.0 | How dense the volume is to the LIGHT, separately from the camera: over 1 casts darker self-shadow, under 1 lets light through. |
| emission_mode | Choice | constant | Where the emission's colour comes from. constant: one colour per unit of the read's emission grid (or its density). blackbody: the read's temperature grid through the Planckian locus, temperature 0 and 1 mapped to the two kelvin knobs, × intensity. constantblackbody |
| temperature_scale | Float | 1.0 | Multiplies the temperature grid before the kelvin mapping. |
| kelvin_at_0 | Float | 1000.0 | Blackbody: the colour temperature where the temperature grid reads 0, kelvin (the cooling edge of the fire). |
| kelvin_at_1 | Float | 3000.0 | Blackbody: the colour temperature where the temperature grid reads 1, kelvin (the core). Physically bright emission keeps the T⁴ magnitude relative to this. |
| renderer | Choice | live | live: the raymarch the viewport draws with. final: the Final renderer — a volumetric path tracer over the same gas, lights and look, every light sampled directly with an exact transmittance and real multiple scattering up to bounces. Slower by spp; deterministic. livefinal |
| spp | Int | 16 | Final renderer: samples a pixel a render. 16 is a look-dev preview with grain; 64–256 is a frame worth keeping. |
| bounces | Int | 4 | Final renderer: how many times light may scatter inside the gas. 1 is single scattering, exactly integrated; 4–8 lights the inside of thick smoke and softens its edges. |
| disabled | Bool | false | Bypass: the node passes its first input through untouched (D in the graph). The knobs keep their values for when it comes back. |
| label | Text | A note shown under the node in the graph — what this node is FOR. Never affects the render or the cache. | |
| hide_input | Bool | false | Draw the node without its input wire — a tidy graph for a node whose source is obvious (a Dot, a viewer tap). |
See also
- The 3D system — How to put geometry, cameras and volumes in the comp — without becoming a 3D application.