FlexSim 2026 RTX Mode Rendering Issue with RTX 5090 Card

[haozhou88FBM]

When I try to turn on RTX mode in FlexSim 2026, the model freezes forever without giving any error messages. The GPU driver version is 581. I have searched a few solutions but none of them work. @philboboADSK, could you please help to take a look.

Gemini reply the potential issue could be as follows:

If the developers of FlexSim compiled the 2026 release using an older version of the OptiX SDK (which is highly likely, as Blackwell was just released), no combination of driver rollbacks or settings changes on your end will fix it. The software literally does not possess the code required to run ray-tracing on a 5090.

The Fix: You will need to reach out directly to FlexSim support. When you do, be highly specific: tell them you are running an RTX 5090 (Blackwell architecture) and that the OptiX engine hard-freezes upon initialization. They may have an internal hotfix patch, or they may be able to provide you with updated optix.dll files to drop into your installation folder until they release an official update.

[philboboADSK]

FlexSim's RTX Mode uses OptiX 6.0. If the latest Nvidia drivers no longer support OptiX 6.0, then RTX Mode won't work with them.

I can add a case to the development list to consider updating RTX Mode to use a newer version of OptiX in order to work with newer versions of Nvidia cards and drivers. This won't be a small task from the development side though. The OptiX SDK has changed drastically since 6.0.

[haozhou88FBM]

Got it. Thanks for the information, Phil.

[JordanLJohnson]

As another data point, I just tested this on a NVIDIA RTX PRO 5000 Blackwell (driver version 582.08) in FlexSim 26.0.0, and it seemed to work without issue, both with and without the denoiser. However, this card is older than your card (according to a quick internet search), so it may not be new enough to have the same issue.

[haozhou88FBM]

Thanks for the information Jordan. It seems Nvidia has very different driver for different type of card even though both card has the similar hardware architecture😭. And unfortunately, I am not able to install the driver that you are currently using for a gaming card.

[logan_gold]

Bug report has been added to the list (FLEXSIM-12839).