Rendering Configuration

Rendering Configuration#

The RenderCfg class controls the renderer, ray-tracing sample count, scoped denoising/reconstruction, tone mapping, DLSS, path-depth limits, and NRD settings used by SimulationManager.

Core options#

Parameter

Type

Default

Description

renderer

str

"auto"

Renderer backend: auto, no-render, hybrid, fast-rt, or rt.

spp

int

1

Samples per pixel for ray-traced rendering. Must be at least 1.

min_bounces

int

4

Path depth at which Russian Roulette may start terminating rays. Must be non-negative.

max_bounces

int

8

Maximum traced path depth, counting the primary segment. Must be positive and at least min_bounces.

denoising

DenoisingCfg

DenoisingCfg()

Independent window/offscreen choices: off, optix, dlss, or nrd.

tone_mapping_enabled

bool

False

Apply modified Reinhard tone mapping to RGB output.

tone_mapping_exposure

float

1.0

Fixed linear exposure multiplier used before tone mapping.

dlss

DLSSCfg

DLSSCfg()

NVIDIA DLSS settings. See NVIDIA DLSS.

nrd

NRDCfg

NRDCfg()

NVIDIA NRD settings for the public nrd path.

The public dlss path maps to DexSim DLSS_RR; the public nrd path maps to standalone DexSim NRD_RELAX. Tone mapping affects RGB output only; depth, segmentation masks, normals, and position buffers remain unchanged.

Bounce limits are validated at construction and again before conversion to DexSim’s WorldConfig, including after mutable config edits. A ray can end on a miss or absorption before min_bounces; that setting controls the start of random path termination rather than guaranteeing a path length. The primary segment has depth zero. The defaults preserve DexSim’s existing path budget.

NRD’s indirect-lighting budget remains controlled by max_indirect_bounces; max_bounces also bounds NRD transparent continuations. Matching the two general bounce limits across denoising modes does not make their light-transport budgets identical.

Renderer selection#

For state-based RL, use RenderCfg(renderer="no-render") with SimulationManagerCfg(headless=True). This selects DexSim’s Renderer.NORENDER backend. EmbodiChain skips background, light and visual-material creation, retains physical ground, and skips Newton render-state publication. Native cameras and windows require hybrid, fast-rt, or rt. headless=True with a native renderer keeps offscreen rendering available.

Policy evaluation accepts --renderer no-render. For visual evaluation of a NoRender checkpoint, --viewer selects Hybrid by default.

With renderer="auto", EmbodiChain selects a backend from the GPU detected at the configured gpu_id when the simulation manager is constructed:

GPU class

Examples

Selected renderer

RTX-series consumer/workstation GPUs

RTX 4090, RTX 6000 Ada

hybrid

Datacenter accelerators

A100, A800, H100, H800, H200, H20

fast-rt

No CUDA device or unknown GPU

—

hybrid

An explicit renderer always takes precedence over automatic selection. The process-wide default can also be changed through SimulationManager.set_default_renderer():

from embodichain.lab.sim import SimulationManager

SimulationManager.set_default_renderer("auto")
SimulationManager.set_default_renderer("fast-rt")

Configuration example#

from embodichain.lab.sim import SimulationManagerCfg
from embodichain.lab.sim.cfg import DenoisingCfg, RenderCfg

sim_config = SimulationManagerCfg(
    render_cfg=RenderCfg(
        renderer="fast-rt",
        spp=4,
        min_bounces=1,
        max_bounces=4,
        denoising=DenoisingCfg(window="dlss", offscreen="nrd"),
        tone_mapping_enabled=True,
        tone_mapping_exposure=1.0,
    )
)

For DLSS-specific settings, see NVIDIA DLSS.

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