aiSim™ – 5.6.0 release notes

Welcome back to another edition of aiSim's Release Notes! We're thrilled to continue sharing the latest breakthroughs and enhancements from our cutting-edge simulation platform, keeping you in the loop with the forefront of automotive simulation technology.

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The v5.6.0 release of aiSim is here! In the new version, we introduced a new raytracer for the radar sensor and LiDAR support for Gaussian splatting, added Controller support for OpenSCENARIOs, and automated parameter distribution to aiFab. We also made numerous enhancements in the aiSim GUI and OpenSCENARIO, as well as rendering and sensor improvements.

Moreover, we improved aiSim's internal simulation scheduling to support fractured sensor update intervals and slowed down real-time simulation. On the content side, we added support for RoadRunner traffic light import and FBX import via the Atlas map importer. We also added a diverse set of 62 pedestrian actors and made several map updates.

Featured Content

New Features

New raytrace-based radar sensor: Implemented an experimental raytracing model for the existing radar sensor, which provides a more accurate radar simulation than the current model.

Parameter variation in aiFab: Added automated parameter distribution file generation for aiFab, enabling seamless OpenSCENARIO integration. The tool assigns default parameter ranges and runs automatically in the backend, ensuring compatibility with aiFab WS while reducing manual effort.

Controller support in OpenSCENARIO: Controllers introduce different driver behaviors with four control domains (lateral, longitudinal, light, and animation). AIM provides the DefaultController (actions are executed without any modification) and DriverOffController (discards actions when active) implementations.

Fractured sensor update intervals: aiSim's internal simulation scheduling has changed significantly to support fractured sensor update intervals. This means that you can have sensors that are operating at, for example, 30 FPS (that is 33⅓ ms update intervals).

Slowed-down real-time simulation: An optional time_multiplier configuration parameter is added for real-time simulations. This value slows down the simulation by factoring all update intervals. This setting enables running aiSim with a stack that can be slowed down with similar time-adjustment options.

Improvements

OpenSCENARIO improvements:

• Added an OpenSCENARIO extension XSD file in the aisim_gui-<version>\data\openscenarios\schemas folder. It contains the supported non-standard language elements.  
• OpenSCENARIO language support is extended with LightStateAction. Using this action, you can control vehicle light states.

Rendering and sensor improvements:

• We've introduced "tiled lighting." In this rendering technique, an algorithm divides the image into tiles, and different light sources in the scene can be culled against the tiles. This results in matching light sources and tiles. Since the light sources are now limited, the GPU can calculate tile lighting faster; hence the improvement in aiSim's shading performance.
• The resources::Camera class (used by camera sensors) performs the main frustum cull on the GPU. However, if a sensor needs the scene capture render lists (e.g., for bounding box or lane data), a CPU-side frustum cull is also needed. Before v5.6.0, this CPU side frustum cull was always enabled regardless of the sensor implementation. With this improvement, a new boolean constructor parameter, cpu_side_frustum_cull_needed, has been introduced in the resources::Camera class for sensor developers to turn on or off this feature when implementing a custom camera sensor.
• Added ambient occlusion rendering for scenario objects on Gaussian splatting maps if a raytrace-based camera sensor is used.
• Added new parameters (affine_transform_parameters; max_valid_reprojected_ray_pixel_distance) to the FTheta camera distortion model to define an affine transformation and to compensate the effect of inaccuracies for calculated coefficient polynomials.
• You can now control (i.e., downscale) the resolution of specific texture types to increase performance and reduce GPU memory usage (see texture_mip_bias_config).
• aiSim now supports high-quality, raytrace-based shadows for raster-based camera sensors (see use_raytrace_shadows).
• The rotation_direction sensor parameter has been added to change the spin direction of the rotating LiDAR from counterclockwise (default) to clockwise.
• Reduced VRAM usage in raster-based camera sensors by merging SSAO components.

aiSim GUI improvements:

• You can set proxy settings in the aiSim GUI if direct access to LicenseSpring (i.e., the licensing solution that aiSim uses) servers is restricted or not possible due to network policies at your organization. This way, you no longer have to edit configuration files to configure proxy settings.
• In the aiSim GUI’s AimScenario and OpenSCENARIO workspaces, you can now select pedestrian models from a drop-down menu when editing Walker-type ScenarioObject parameters (in AimScenario) or Pedestrian-type Entity parameters (in OpenSCENARIO). For further details and limitations, visit the AimScenario and OpenSCENARIO pages.
• Users can now parameterize Vehicle Light Event parameters using the AimScenario Editor workspace. This can simplify working with scenarios that involve switching between, for example, low beams and high beams.
• The management of tagged enumerated types in the AimScenario workspace and parametrized enumerated types in the OpenSCENARIO editor workspace has been improved. The content of "Default values" is now automatically filtered based on the content of "Possible values." The Select All and Deselect All options have also been introduced to improve user experience.
• We have added a new parameter generation mode to aiFab, Latin Hypercube, that randomly samples a parameter space while ensuring even coverage to reduce clustering and gaps.
• Cube positions are now updated when an already defined parameter is applied to them.
• The Parameter Editor panel now displays more units and its input fields have been widened for a better user experience.

OSI ground truth (GT) information can now be acquired from the simulation via client-side functions. By default, OSI GT is exported and saved into a Protocol Buffer (protobuf) file automatically.

There is a new parameter in the segmentation settings config file, named sky_segmentation_semantic_label. You can specify the expected semantic label for the sky, allowing you to use a custom semantic label for the sky.

Added example configuration files for aiFab. An additional scenario was also added that highlights the metric-dependent outcome of adaptive iterations.

Content Pipeline Updates

New Features

FBX import via Atlas: aiSim's Atlas map importer now supports importing an FBX file. The imported FBX file can be combined with any external map logic as long as it supports scenario creation.

RoadRunner traffic light import: Added a RoadRunner (RR) export preset that allows more data to be exported into the RR export files–which now include RoadRunner's own Traffic Light descriptions. If you export a scene using this export configuration, the importer can place the traffic lights on an aiSim map.

New 3D assets in Asset Library

New buildings, props, vehicles and more.

Map updates

Extended the Highway_HU_M0_11_Roundabout map to each direction by about 100 meters.

Junction layer has now been added to the following maps to the base asset package

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