Liquid Simulation doesn't run (3d Max 2026)

[Nesshi]

Hello,

I'm trying to run a liquid simulation in 3ds Max 2026, but it simply won’t start.

I've tried several solutions — including reinstalling 3ds Max and even formatting my computer — but nothing has changed.

To rule out scene complexity, I created a very simple test setup (as shown in the attached image). However, even with just a box and a plane, the simulation remains stuck on Sim Idle — the play button is disabled, as you can see in the screenshot.

The settings of my PC are:

"Processor AMD Ryzen 9 3900X 12-Core Processor (3.80 GHz)
Installed RAM 32.0 GB
System type: 64‑bit operating system, x64‑based processor

Edition Windows: 11 Home Version 25H2
Installed on 11/11/2025
OS build: 26200.7462"

[wernienst]

Yes, in fact, there might be differences depending on local settings.

For example, if I run the test file with "Use File Units..." checked, I get this at Frame 10:

71333 particles, 0.453s average frame time

If I check "Rescale File Units...", I get this (System Unit is millimeters):

524216 particles, 1.436s average frame time

Furthermore,

as I mentioned before, I couldn't run the simulation on first attempt.

That's probably because my Max (installed on C:\!) didn't find the given SimCache Directories (I haven't run Fluid before with this Max version, and my general Documents folder is not at the default location \users\username\).

After restarting it created its own SimCache directories and then it worked - always. I can't even force the simulation to NOT run by deleting the SimCache directories 😏

[Nesshi · Accepted solution]

Hello @klankster, thanks for the help.

Well, your process adds yet another layer of strangeness to this whole situation 😅

I had been dealing with a Liquid Simulation issue that simply couldn’t resolve in any way, and due to Copilot’s suggestion, I even started to believe it might be related to student‑license limitations. Even after formatting my computer and reinstalling 3ds Max several times (around 4x), completely clean and without any plugins (including Corona Renderer), the problem persisted.

Gemini initially suggested that I create a folder for the SimCache, but even then, it didn’t work.

Unlike Copilot, Gemini explained that the Liquid Simulation system depends on Bifrost — since I have almost zero knowledge of hardware/software engineering, I wouldn’t be able to explain it properly, but I’ll leave here the answer it gave me.

In the end, Gemini’s suggestion (the last suggestion that solved my issue) was precisely to install 3ds Max on the main drive (C:), and after doing that, Liquid Simulation is now working perfectly. These differences in behavior between our devices really are quite mysterious.

[Nesshi]

So, @wernienst, the fact that 3ds Max isn’t installed in the same directory as the system does indeed affect Liquid Simulation’s behavior.

But in my case, even after creating a specific folder for the SimCache, it still didn’t work — it only started working once I installed 3ds Max on the system drive.

PS: where did you manage to see the bit rate during the simulation?

[klankster]

One problem we had at one point was that if the computer's locale settings were using a comma as the decimal separator, some of the XML control files would be written with commas (i.e. 123.45 would end up as "123,45" in the text) and things would fail. I'm pretty sure all those issues have been fixed, but you never know.

In any event, I'm glad you were able to resolve the problem.

-Tom

[lauri_barnhart]

Hello, @Nesshi,

Did the information provided by @MartinBeh, @wernienst or @klankster help you and answer your question?

If yes, please click on the "Accept Solution" button on the post(s) that solved your problem. This will assist other community users in finding and benefiting from this information.

If not, please do not hesitate to give an update in this thread so all community members receive an update on the progression of your question, and can suggest next steps that may be helpful for you to achieve what you're looking for.

All the best,

Lauri | Community Manager

[Nesshi]

Hello @klankster,

So, this is the thing: my second partition didn’t have any special characters — not even in the software installation folder.

The folder was named “Arquivos de Programa” and 🤔 unless the spaces between the words were causing some kind of trouble during the process.

But now everything is running properly 😁

Thank you for the support.