Unable to render image topics in HMI after restarting standalone application

[sandman]

Hi, I am using a standalone Unity build (v2019.4.23f1) with ROS2 dashing on Ubuntu 18.04, as an HMI application. After a fresh reboot I am able to see the image topics nicely in the HMI. However, when I stop the HMI and restart it, only one of the image topics is seen in the HMI.

However all the other image topics are seen without any issues on rqt. This seems to be an issue with the Unity - ROS2 integration (possible environment vars or paths). Any tips on how to debug this issue are much appreciated.

Thanks, Sandip

[samiamlabs]

Hmm, this is not something I have run into before.

Are you using cyclone DDS on the ROS2 side or something else? If not I would start by changing to cyclone and seeing if that makes any difference.

Is it always the same image topic that stops working or different ones every time?

[sandman]

Appreciate your swift response.

I am using FastRTPS. It is always the same image topics that stop working. One specific topic works always. All image topics are equivalent (i.e. nothing special/different about them)

[sandman]

I am using eProsima Fast DDS to be specific.

[samiamlabs]

Have you tried logging or something in the image callbacks in Unity for the topics that stop showing up?