The scratch cache is a temporary cache to speed up playback and scrubbing. It is intended for quick previews at low-to-medium resolutions, unlike user caches which are intended for the final, high-resolution result.
The scratch cache stores the simulated frames in memory, and offloads them to temporary files on disk. It is automatically flushed and regenerated when you change the simulation and return to the first frame. It also gets deleted automatically when you close the scene.
- Make sure that
Playback speed is set to
Play every frame in your
preferences.
- Select
, and make sure that the options are set as you want them. In particular, make sure that
Maximum RAM Usage (GB) is less than your system memory minus some overhead. See
Bifrost Options.
- Make sure that
Scratch Cache is enabled on the main container node (e.g.
bifrostLiquid or
bifrostAero).
Note: You can use
Enable Scratch Caching in the
Bifrost Options dialog box to toggle
Scratch Cache on or off for all container nodes in the scene.
- Go to the start frame of the simulation.
By default, the start frame is 1 but you can set a different value in the container's attributes.
- Do any one of the following:
- Step forward.
- Play back. You can stop playback at any time.
- Go to any later frame on the timeline, if
Run up to current time is set in your
Dynamics preferences.
If
Enable Background Processing is on in the
Bifrost Options dialog box:
- All frames in the specified range are sent to the Bifröst Computation Server.
- You can start playing or scrubbing through the frames as they are being computed.
- You can stop the processing of frames in the queue by clicking
Stop at the bottom right of the Maya window, or by choosing
. Note that processing will stop only after the current frame is finished.
If
Enable Background Processing is off, then you must wait for all frames to be processed before you can interact in Maya.
- If you change the simulation settings or modify the input objects, the cached frames get marked as "dirty".
- You can still play or scrub through any frame except the first frame of the simulation to view the cached results, but they will not reflect the changes you made.
- When you return to the first frame of the simulation, the cache is flushed automatically. The updated results of the simulation will be recached as you play back or step forward again.
- If desired, you can flush the frames manually by selecting the main container or shape object and choosing
. You can then re-cache the frames by repeating steps 4 and 5.
Tip: You can activate
to show the number of Bifrost particles and voxels as a heads-up display, as well as the number of time steps per frame. The values reflect the actual numbers of elements in the scene and in the selected objects, and not the numbers of elements being drawn in the viewport (which can be adjusted using
Max Particle Display Count in the
bifrostShape attributes's attributes).