# \[AODT v.1.5.0\] EM solver - Configurability of Ray Propagation

**URL:** <https://forums.developer.nvidia.com/t/aodt-v-1-5-0-em-solver-configurability-of-ray-propagation/379784>\
**Category:** Aerial Forum\
**Tags:** aerial-omniverse-digital-twin\
**Created:** [August 11, 2026, 2:45am UTC](https://forums.developer.nvidia.com/t/aodt-v-1-5-0-em-solver-configurability-of-ray-propagation/379784 "2026-08-11T02:45:11Z")\
**Posts on this page:** 4\
**Page:** 1

<div class="post-metadata">

**Author:** ![mhseo10](https://developer.download.nvidia.com/images/forums/profile-default-devtalk-84.png) [@mhseo10](https://forums.developer.nvidia.com/u/mhseo10)\
**Post date:** [August 11, 2026, 2:45am UTC](https://forums.developer.nvidia.com/t/aodt-v-1-5-0-em-solver-configurability-of-ray-propagation/379784/1 "2026-08-11T02:45:12Z")

</div>

Hi,

We are currently using AODT to investigate NTN propagation scenarios.

We observed that the number of detected ray paths decreases significantly as the RU altitude increases. In our experiments, the number of LoS paths starts to decrease at around 7 km, and no viable ray paths are detected above approximately 10 km.

[5km]

 ![image](https://global.discourse-cdn.com/nvidia/original/4X/d/b/8/db8003f17bbd42eac34c136aa8128b592e3f1f10.jpeg)

[8km]

 ![image](https://global.discourse-cdn.com/nvidia/original/4X/b/7/c/b7c156126a9f47098e12e4ba624bc6176cfb5dda.jpeg)

We have a few questions regarding the ray-tracing configuration:

1. Is it possible to configure the **angular distribution** or **resolution** of the initial rays, for example by restricting the ray search to a specific angular region toward the target UE, rather than only increasing the `sim_em_rays`?
2. The low-level EM Solver API provides `RTConfig::rx_sphere_radius_cm`, but we could not find an equivalent option in the Python `SimConfig` API or YAML configuration. **Is there a supported way to configure the UE reception sphere radius**?

Thank you.

---

<div class="post-metadata">

**Author:** ![kpasad1](https://sea2.discourse-cdn.com/nvidia/user_avatar/forums.developer.nvidia.com/kpasad1/32/435018_2.png) [@kpasad1](https://forums.developer.nvidia.com/u/kpasad1)\
**Post date:** [August 14, 2026, 4:40am UTC](https://forums.developer.nvidia.com/t/aodt-v-1-5-0-em-solver-configurability-of-ray-propagation/379784/2 "2026-08-14T04:40:27Z")

</div>

@mhseo10

Unfortunately, AODT cannot restrict the rays to a specific region. Note that a NLoS may appear from a location anywhere on the map, so restricting the rays to a angular distribution is not correct. You can add a directional antenna gain to increase the power of the rays.

With 1.5.0, you can shoot 10’s of millions of rays. Please try as large as your map/antenna configuration allows.

The UE reception sphere radius is not available via yaml (it will be exposed in 1.6). However you can overwrite its default value in assets/scenrio.json . This file is uploaded to the s3 bucket.

---

<div class="post-metadata">

**Author:** ![mhseo10](https://developer.download.nvidia.com/images/forums/profile-default-devtalk-84.png) [@mhseo10](https://forums.developer.nvidia.com/u/mhseo10)\
**Post date:** [August 18, 2026, 2:16am UTC](https://forums.developer.nvidia.com/t/aodt-v-1-5-0-em-solver-configurability-of-ray-propagation/379784/3 "2026-08-18T02:16:21Z")

</div>

The above results were obtained using a map with an area of approximately 15km^2 and 40 million rays. Following your suggestion, we changed `sim_em_sphere_radius` in `assets/scenario.json` to 10 m, but the following error occurred:

 ![image](https://global.discourse-cdn.com/nvidia/original/4X/4/b/6/4b6d8159b2da2427e916de702e4b2797bd38e380.png)

Is there any way to configure `sim_em_sphere_radius` to a value larger than 2 m in the current version? Also, are there any plans to support NTN simulation scenarios in future releases, including configurations suitable for much longer propagation distances?

---

<div class="post-metadata">

**Author:** ![system](https://sea2.discourse-cdn.com/nvidia/user_avatar/forums.developer.nvidia.com/system/32/68080_2.png) [@system](https://forums.developer.nvidia.com/u/system)\
**Post date:** [September 1, 2026, 2:16am UTC](https://forums.developer.nvidia.com/t/aodt-v-1-5-0-em-solver-configurability-of-ray-propagation/379784/4 "2026-09-01T02:16:55Z")

</div>

This topic was automatically closed 14 days after the last reply. New replies are no longer allowed.