Rays pass through buildings and ground

[kenny223sns]

Hello,

I am currently working on a simulation using Sionna RT, where I would like to ensure that no propagation path exists between the transmitter and receiver if all line-of-sight (LoS) and reflected paths are completely blocked by buildings or other obstacles.

However, I encountered an issue when computing propagation paths: some rays appear to pass through buildings and even the ground, as shown in the attached images. I was expecting that paths would be blocked(no paths), but instead rays going through structures.

import numpy as np, matplotlib.pyplot as plt, sionna, tensorflow as tf          
from sionna.rt import load_scene, PlanarArray, Transmitter, Receiver,PathSolver


scene = load_scene(sionna.rt.scene.munich)

scene.tx_array = PlanarArray(num_rows=4, num_cols=8,  
                             horizontal_spacing=0.5,  
                             vertical_spacing=2.0,    
                             pattern="tr38901", polarization="V")
scene.rx_array = PlanarArray(num_rows=1, num_cols=2,
                             horizontal_spacing=0.5, vertical_spacing=0.5,
                             pattern="tr38901", polarization="V")

scene.remove("bs"); scene.remove("ue")
bs = Transmitter(name="bs",
                 position=[0,0,50],
                 )
# Create a receiver
ue = Receiver(name="ue",
              position=[100,100,-10],
              )
scene.add(ue)
scene.add(bs)
bs.look_at(ue) 


p_solver  = PathSolver()
# Compute propagation paths
paths = p_solver(scene=scene,
                 max_depth=5,
                 los=True,
                 specular_reflection=True,
                 diffuse_reflection=False,
                 refraction=True,
                 synthetic_array=False)

scene.preview(paths = paths)

• Could this be caused by the receiver being placed below ground level (z = -10)?
• Should I explicitly modify the material properties of buildings or the ground to enforce
  proper blocking behavior?

Appreciate any guidance or clarification

Screenshots:

[jhoydis]

Hi @kenny223sns,

You can just turn off refraction.

[oxelarnal]

Hello @kenny223sns ,
I have the same problem. Have you found any solution???

[jhoydis]

Hi @kenny223sns,

I think that I have already said it above. You can simply disable refraction. Why does this not solve your problem?

[kenny223sns]

HelIo @oxelarnal ,
I managed to fix it by following @jhoydis's suggestion — disabling refraction solved the problem in my case.