Rendering

The execution model is in

blender-core

. Scene lighting and cameras are in

blender-lighting-lookdev

One call

scripts/render_batch.py -- --engine CYCLES --preset final --res 1920 1080 --out //render/hero_#### --frames 1
scripts/render_batch.py -- --preset preview --frames 1-120 --format MP4 --out //render/turntable
scripts/render_batch.py -- --cameras CamA CamB CamC --format EXR_MULTI --out //render/shots/

Presets:

preview

(Cycles 64 spp, threshold 0.05, 50% res; EEVEE 16),

final

(512 spp, 0.01; EEVEE 128 + raytracing),

product

(1024 spp, transparent background). GPU is picked automatically (OptiX > CUDA > HIP > Metal > oneAPI), and the denoiser matches (OptiX or OpenImageDenoise).

Engine choice

Engine	Use	Notes
Cycles	final quality, product, archviz, glass/SSS/caustics, baking	path tracer; set the GPU; adaptive sampling + denoise
EEVEE (5.x, ex-"Next")	fast look-dev, stylized, motion graphics, previews	ray-traced reflections/GI ( `use_raytracing` ), virtual shadow maps; needs a GPU even headless
Workbench	playblasts, clay/matcap reviews, QA sheets	instant, no lighting accuracy
Engine ids: `CYCLES` , `BLENDER_EEVEE` , `BLENDER_WORKBENCH` .

Cycles quality levers (ordered by impact)

Adaptive sampling (
```
adaptive_threshold
```
0.01 final / 0.05 preview) + denoise (OIDN with albedo+normal passes,
```
denoising_input_passes="RGB_ALBEDO_NORMAL"
```
). Raising samples alone is the least efficient fix.
Light paths: interiors need diffuse bounces ≥ 4. Product shots: total 12, glossy 4, transmission 8–12 for glass. Clamp indirect 5–10 kills fireflies at a small energy cost.
Light tree (
```
use_light_tree
```
, on) for many lights. Path guiding (CPU only) for difficult indirect light.
Fewer, larger lights beat many small ones. Emissive meshes are noisier than area lights.
Persistent data (
```
render.use_persistent_data
```
) speeds up animations and turntables. Use
```
simplify
```
(max subdivision, texture limit) for previews.
5.2: texture cache (
```
render.use_texture_cache
```
,
```
use_auto_generate_texture_cache
```
) cuts memory in texture-heavy scenes by generating
```
.tx
```
mip tiles.

Color management (decide once per project)

AgX (default): photographic, handles bright highlights. Looks:
```
AgX - Punchy
```
,
```
- Base Contrast
```
...
Khronos PBR Neutral: shows albedo faithfully. Use it for product/e-commerce and asset reviews, and to match three.js
```
NeutralToneMapping
```
.
Standard: graphics/UI/texture output that must match pixel values.
ACES 1.3 / 2.0: VFX pipelines (plates, other DCCs).
Use exposure (
```
view_settings.exposure
```
), not light power, for global brightness tweaks. Display device sRGB, or Display P3 / Rec.2100 for HDR delivery.

Output formats

Stills: PNG 8/16-bit (RGBA when the film is transparent) or JPEG for web previews.
Comp/VFX: EXR multilayer (
```
EXR_MULTI
```
, DWAA 16-bit) with passes (Denoising Data, Cryptomatte, AO, Mist, Z). 5.0 renamed passes:
```
Diffuse Color
```
,
```
Depth
```
, etc.
Video: render frames first (PNG/EXR), then encode (FFmpeg or the VSE), because a crash mid-MP4 loses everything. Direct MP4 is fine for previews. Set
```
image_settings.media_type
```
before
```
file_format
```
(5.0+).
Transparent:
```
film_transparent=True
```
+ PNG/EXR. A glass-only alpha needs
```
film_transparent_glass
```
.

Compositor (5.0+ API)

python

ng = bpy.data.node_groups.new("Comp", "CompositorNodeTree"); scene.compositing_node_group = ng
ng.interface.new_socket("Image", in_out="OUTPUT", socket_type="NodeSocketColor")
rl, glare, out = ng.nodes.new("CompositorNodeRLayers"), ng.nodes.new("CompositorNodeGlare"), ng.nodes.new("NodeGroupOutput")
ng.links.new(rl.outputs["Image"], glare.inputs["Image"]); ng.links.new(glare.outputs["Image"], out.inputs[0])

There's no Composite node anymore: the group output is the final image. Many node options are now input sockets (Glare

Type

Threshold

Strength

), so

--describe

them with

blender-geometry-nodes/scripts/gn_builder.py

. File Output node:

directory

file_name

file_output_items

CLI rendering (render farms, CI)

blender -b scene.blend -E CYCLES -o //out/frame_#### -F PNG -s 1 -e 120 -a

renders an animation.

-f 10

renders a single frame. Python args go after

--

```
-- --cycles-device OPTIX
```
(or CUDA/HIP/METAL/ONEAPI) selects the device without Python.
Split frames across machines with
```
-s/-e
```
, or with Placeholders + No Overwrite (
```
render.use_placeholder
```
,
```
use_overwrite=False
```
) on shared storage.

Gotchas

```
scene.render.engine
```
enum under-reports (add-on engines). Assign in try/except (the script does).
EEVEE in background still needs a GPU context. In CI without a GPU, use Cycles CPU or Workbench.

bpy.ops.render.render(write_still=True)

writes

render.filepath

. Without

write_still

, the result only lives in

Render Result

Noise in glass/caustics: enable caustics only if needed (
```
caustics_refractive
```
), raise transmission bounces, or fake it with Thin Wall (5.2) for windows.
Fireflies: clamp indirect, a filter glossy / blur glossy (
```
blur_glossy
```
0.5–1), and bigger light sources.

blender-rendering

NPX Install

Tags

SKILL.md Content