A tyFlow simulation crash before the cache finishes is often a memory problem during export, and the tyFlow docs describe several ways to reduce it.
Technical Brief // tyFlow Cache Export Failures
A documentation-based look at why a tyFlow simulation crash can happen while exporting a cache in 3ds Max, based on the official tyFlow Export Particles page.
- RAM Is the Documented Risk: by default, processed particles go into the tyFlow cache, and exporting more particles than RAM can hold may make 3ds Max run out of memory and fail.
- Disable the Cache for Huge Exports: the docs advise turning the tyFlow cache off before a very large export, and note that Deadline ignores caching.
- Protect Long Exports: tyCache Backup at regular intervals lets a partial cache load after a crash, but it can add significant time, and PRT Skip existing files skips complete partitions.
- Practical Production Fix: split the export, cache to disk, and keep the farm for rendering. For heavy simulation caches on cloud, see 3ds Max cloud rendering guide. Cache first, render second.
A tyFlow simulation crash that ends the job before the cache finishes wastes the most expensive part of the shot: the time you already spent simulating. The official docs do not publish a crash checklist, but the Export Particles page describes several settings that directly affect memory use and how much work survives a failure.
This guide collects those documented settings and turns them into five practical fixes. It covers 3ds Max exports only, and it labels our own reading separately from what tyFlow states.
Contents
Why does a tyFlow simulation crash before the cache finishes?
The main documented cause of a tyFlow simulation crash during tyCache export is memory. By default, processed particles go into the tyFlow cache when caching is enabled, and the docs warn that exporting more particles than RAM can hold may cause 3ds Max to run out of memory and fail (tyFlow Export Particles).
For 3ds Max failing during export, memory is the only cause that page gives, so treat other triggers, such as plugin conflicts or driver problems, as unverified until you test them. The page separately warns about downstream crashes: the legacy Maya Alembic importer may crash on tyFlow Alembic data, and Unreal Engine can crash during playback unless the no empty frames and material ID face sets options are enabled.
What does tyFlow keep in memory while you export a cache?
tyFlow keeps processed particles in its cache by default, which is why a large export can exhaust RAM. Two documented details matter: the export only runs when you press the Export button or start it from MAXScript, because the simulation itself does not evaluate the operator, and Deadline ignores caching.
For exports that you know are huge, the docs say to disable the tyFlow cache first. In practice that means a tyFlow simulation crash risk is highest when a long, dense flow is exported in one pass with the cache still enabled (our interpretation).
Which tyFlow export mode fits a heavy simulation?
The export mode decides what is written to disk and how large it gets. The table summarizes the documented behavior of the modes most relevant to large caches.
| Export mode | What the docs state | Why it matters for a crash |
|---|---|---|
| tyCache | Writes per-frame files and a mesh file named xxx_tyMesh.tyc. Options include Combine meshes per-frame and Backup at regular intervals. | Has the most documented memory and recovery options. |
| PRT | Writes a .prt sequence. Skip existing files skips complete partitions, while incomplete partitions still update the flow. | Complete partitions are skipped, but incomplete ones still have to be re-processed. |
| Alembic Mesh | Single collapsed mesh usually creates extremely large files. Node per particle gives much smaller files and more efficient loading. | Smaller files reduce disk and loading problems. |
| Objects | Converts particles to scene objects. Auto-export on render creates objects at render start and deletes them at the end. | Can avoid the viewport slowdown from huge exports. |
Source: tyFlow Export Particles documentation, checked October 2026.
How do you fix a tyFlow simulation crash during cache export?
These five fixes follow the settings the tyFlow docs describe. Try them in order, and test each on a short frame range before committing to the full cache.
- Disable the tyFlow cache before a huge export. The docs recommend this for huge exports, meaning more particles than RAM can hold.
- Use Combine meshes per-frame for mesh-heavy flows. It merges meshes per frame and disables instancing, but stores mesh data in per-frame files, which can reduce RAM use when keep frames in RAM is off (a RAM reduction, not a documented crash fix).
- Enable Backup at regular intervals on long exports. It periodically updates the mesh file during export so a partial cache can still load if the export crashes. The docs warn it can add significant time for large mesh data, so disable it if the export is likely to finish.
- Export PRT in partitions. Skip existing files skips complete partitions. Keep the total partition count high so later exports stay in the same PRTLoader sequence.
- Choose a lighter Alembic mode. Node per particle exports meshes once per file and updates transforms per frame, which gives much smaller files than a single collapsed mesh.
What should you check when a tyFlow export runs through Deadline?
Two documented points apply to Deadline, which matters if a tyFlow simulation crash only appears on the farm. Deadline ignores tyFlow caching, and the Suppress all popups option can help Deadline popup detection in UI-mode exports.
If a farm export fails while the same flow works locally, compare these settings first, then compare available RAM on the machine (our interpretation).
When should you cache locally and render on a farm?
Cache locally when you need to iterate on the simulation or debug a tyFlow simulation crash, and move to a farm once the cache is stable and the remaining work is rendering. A finished cache on disk also makes the render step more predictable. We compare farm options for this workflow in 3ds Max cloud rendering guide.
Slow or unstable software is a wider problem than one plugin. See our guides on Blender viewport lag with heavy scenes and Maya playblast vs final render differences for the same preview-versus-final thinking in other tools.
Conclusion
A tyFlow simulation crash during cache export most often points to memory, and the tyFlow docs describe settings that reduce RAM use or limit lost work. The documented levers are the tyFlow cache, Combine meshes per-frame, Backup at regular intervals, PRT partitions and the Alembic mesh mode.
- Disable the tyFlow cache before a huge export.
- Export in partitions or enable backups so a crash does not cost the whole run.
- Test the settings on a short range before the full cache, so a tyFlow simulation crash shows up early.
FAQ
Why does my tyFlow simulation crash during cache export?
The tyFlow docs state that exporting more particles than RAM can hold may cause 3ds Max to run out of memory and fail, because processed particles go into the tyFlow cache by default. For huge exports, disable the tyFlow cache first.
Does tyFlow keep a partial cache if the export crashes?
For tyCache exports, the Backup at regular intervals option periodically updates the mesh file during export so a partial cache can still load if the export crashes before the mesh file is created. It can add significant time for large mesh data.
How do I resume a tyFlow PRT export?
The PRT mode has a Skip existing files option that skips complete partitions. Incomplete partitions still update the flow because of history dependence, so some recomputation can remain.
Which Alembic mode gives smaller tyFlow files?
According to the docs, Node per particle exports meshes once per file and updates transforms per frame, giving much smaller files than a single collapsed mesh, which usually creates extremely large files.
Does Deadline use the tyFlow cache?
The tyFlow docs state that Deadline ignores caching. They also note that Suppress all popups can help Deadline popup detection in UI-mode exports.
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