Crash linked to RailClone when starting Corona Interactive rendering

[hadrien]

Hi iToosoft team and users,
Lately I have noticed a very odd pattern. In some scenes, when previewing a camera, I can't use Interactive rendering without having 3ds Max to crash instantly. I've noticed that this only happens when RailClone objects are visible in the Layers (they don't have to be visible by the camera).
On the Corona forum, the workaround I've found is to start a normal rendering with one pass, and then Interactive Rendering works again.
I've been able to reproduce this crash with a simple box replacing the segment, just to make sure it wasn't an issue with a segment.
From my understanding, Interactive rendering works fine in a non camera viewport.
Attached is the XML file created by 3DS max when crashing (minidump was too heavy). Is there anyone who had a similar issue and who could tell me how to solve it ?
Thank you in advance for your help !

Configuration :
3DS Max 2025.3 (version 27.0 - 27.3.0.30874)
Corona version 12 Update 1 (Hotfix 1)
RailClone Pro 6.3.9 Network licence

[Michal Karmazín]

HI,

I'm sorry to hear you're experiencing these troubles. Could you please save and send us the minidump file of the crash? If you can reproduce the issue with a minimal scene, it would be ideal if you could send us that as well. Thank you in advance.

Best regards,

[hadrien]

Hi Michal,
Thank you for your quick reply. For some reasons, I haven't experienced the crash on my iterations of the scene since the workaround was used (rendering one pass), without changing anything on the Railclone object or the camera.
However, I have tested a minimal scene with only the faulty camera and the faulty Railclone object. There are no bitmaps, no HDRI, no materials left, only the camera and the Railclone object + segments and a basic sky. I was able to nail the problem down to the camera. If I create a new camera, that one will work normally, and potentially solve the problem once Interactive rendering is started on it. Note that my faulty camera was animated (transform and parameters), and that might have a consequence, although i was able to reproduce the crash after deleting all animation keys.
These crashes only happen when a Railclone object is displayed in the layers, and that's why I think there might be a strange conflict somewhere with Interactive Rendering and the camera. I've sent these elements by e-mail, hope you can reproduce the bug !
I am sending you the minimal scene, the minidump and the xml for the same scene. Thank you for your help.
Best regards,
Hadrien

[iToo]

We could identify the crash in one of the Max libraries used for mesh processing, when called from Corona.

I just contacted with the Corona team, so they take a look to it.

[hadrien]

Thank you so much for investigating and contacting the Corona team. That's far beyond my knowledge and I hope they will help you solve this bug, maybe in a future version. At least I know it's not exactly an error in my scenes, although I would happily change anything that I've been doing wrong the whole time.

[iToo]

Please, would you try to render your production scene using the latest Corona nightly build ?
Test scene renders fine using it. Possibly there was some problem which is already fixed in latest builds.