Tutorial 6: Advanced Rendering#

Objective: Learn how to use different rendering techniques for varying quality/performance trade-offs.

What you’ll learn:

  • Rasterization vs Ray Tracing vs Path Tracing

  • Configuring render modes in MetaSim

  • When to use each rendering technique

Prerequisites: Completed Tutorial 5: Hybrid Simulation

Estimated time: 20 minutes

MetaSim supports multiple rendering techniques through Isaac Sim’s rendering backend. Choose based on your quality vs performance requirements.

Technique

--render.mode

Quality

Speed

Use Case

Rasterization

rasterization

Good

Fast

Training, real-time

Ray Tracing (RTX Real-Time, legacy)

raytracing

Great

Medium

Validation, demos

Real-Time Path Tracing (RTX Real-Time 2.0)

realtime_pathtracing

Great

Medium

Interactive path-traced rendering (recent Isaac Sim)

Path Tracing (RTX Interactive)

pathtracing

Best

Slow

Final renders, sim2real

realtime_pathtracing selects Isaac Sim’s “RTX - Real-Time 2.0” renderer (/rtx/rendermode=RealTimePathTracing). The renderer must be registered at Kit boot — it only joins the render-mode list when /rtx-transient/rt2Enabled is on (derived at startup from the persistent preference /persistent/rtx/modes/rt2/enabled); without registration every /rtx/rendermode write is silently refused. MetaSim injects the registration flags into Kit’s boot argv when it launches the SimulationApp itself, engages the mode, and verifies via readback (once registered, the mode also switches in/out at runtime). If you hand the handler an already-running simulation_app, launch it with --/persistent/rtx/modes/rt2/enabled=true --/rtx-transient/rt2Enabled=true yourself. On builds without RTX Real-Time 2.0 MetaSim raises an explicit error so you can fall back to raytracing or pathtracing.

Running the Tutorial#

python get_started/6_advanced_rendering.py  --render.mode=[rasterization|raytracing|pathtracing|realtime_pathtracing]

you can also render in the headless mode by adding --headless flag. By using this, there will be no window popping up and the rendering will also be faster.

By running the above command, you will simulate a hybrid system and it will automatically record a video. Here we demonstrate how to use one simulator for physics simulation and another simulator for rendering.

Examples#

Ray Tracing#

python get_started/6_advanced_rendering.py  --render.mode=raytracing

Path Tracing#

python get_started/6_advanced_rendering.py  --render.mode=pathtracing

You will get the following images:#

Ray Tracing

Path Tracing

Ray Tracing

Path Tracing