The Point Cache modifier lets you store modifier and sub-object animation to a disk file that records only changes in vertex positions, and then play back the animation using the information in the disk file instead of the modifier keyframes.
Point Cache is useful when the computation required for vertex animation becomes so excessive that it causes animation playback to run slowly or drop frames. Another use for this modifier is to apply the same animation to a number of objects, varying the Start Time and Strength settings for each so they don't all move identically.
The Point Cache modifier is also available in a world-space version, for which usage is the same.
Special features in the Point Cache modifier include:
Cache files for large meshes and long animations can be very large. Saving as a file per frame lets you manage data more easily and replace single frames if you find errors.
Following is a suggested workflow for using Point Cache for working on an animation project in both 3ds Max and Autodesk Maya:
In
3ds Max, use the Point Cache Reload command; this updates the animation to that saved from Maya.
Both versions of the Point Cache modifier provide enhanced animation capabilities, including:
To use the Point Cache modifier:
If the animation is a good candidate for caching, the playback will drop many frames with Real Time Playback turned on, and will run slowly with Real Time Playback turned off.
3ds Max records the animation to the cache file. When finished, the cache file name appears in the Cache File group.
This turns off all the object's modifiers below Point Cache so that only the cached vertex animation will appear when you play back the animation.
This time the animation plays back quickly and smoothly.
Contains settings for recording vertex animation.
After you specify or load a cache file, its name appears in this field.
Creates a new, empty cache file. After setting a new file, use Record to create the cache data.
You can save the file in either of two formats:
Loads a vertex animation from a cache file on disk into the Point Cache modifier. If the number of vertices in the cache does not match the number of vertices in the object, the Cache Info group reports an error, and the animation doesn’t take effect.
Load supports these file formats: XML, PC2, PTS.
Temporarily frees the current cache file, so it can be edited or deleted externally.
Reopens the current cache file, if previously unloaded.
Displays cache statistics in read-only format, including the number of files, point count, evaluations (number of samples), sample rate, start and end frames, and errors, if any.
Contains settings for recording cached animation.
Choose whether to save the cache in a single file, or in a separate file for each frame of recorded animation. The latter option is available only when using the XML file format.
Sets the first frame for recording the vertex animation. Default=first frame of the active time segment.
Using decimal fractions lets you start at a sub-frame setting when using a Frame:Ticks time display.
Sets the last frame for recording the vertex animation. Default=last frame of the active time segment.
Using decimal fractions lets you start at a sub-frame setting when using a Frame:Ticks time display.
Sets the number of frames between each recorded sample. When rendering with motion blur, which uses sub-frame sampling, decrease this value. Default=1.0.
At the default value of 1.0, Point Cache records one sample per frame. Increasing the value causes a sample to be recorded every Nth frame. For example, a value of 10.0 records every tenth frame. Decreasing the value causes multiple samples to be recorded for each frame. For example, if you set Sample Rate to 0.1, Point Cache records 10 samples per frame at evenly spaced intervals.
Stores the vertex animation to a disk file. If no cache file is specified, or the specified file doesn't exist, activates the Save Points dialog, which lets you specify a path and file name for the cache file. Click Save to record the file, and then load it into the Point Cache modifier, ready for playback.
Turns on all stack modifiers below the Point Cache modifier. Use this when you want to change modifier settings.
Turns off all the object's stack modifiers below Point Cache so that only the cached vertex animation appears when you play back the animation.
These options apply only to PC2 and PTS files; when the cache file type is XML they are unavailable.
The method the modifier uses to load the cache file. The options are:
Be conservative in using this, as it can consume a great deal of memory. However, if one cache file is used by several objects, the cache is loaded into memory only once.
These options apply if 3ds Max is running as a network-rendering client; see the preceding for details. In this situation, only Per-Sample and Pre-Load are available, and the default option is Per-Sample, so the clients don't lock files.
This read-only field displays the size of the pre-loaded data when Local is set to Pre-Load.
Affects the motion relative to the original animation. Default=1.0. Range=-10.0 to 10.0.
When modifiers below the Point Cache modifier are enabled, the Strength value is used only when Relative Offset is on. When modifiers below the Point Cache modifier are disabled, the Strength value is always used.
At 1.0, the animation plays back the same as recorded. With strengths between 0.0 and 1.0, the animation is relatively restrained. At strengths greater than 1, the animation is exaggerated. With negative Strength settings, the motion is reversed.
Enables offsetting the animated vertex positions relative to their positions as recorded, based on the Strength setting. Default=off.
When off, only the active vertex selection is animated. In this case, for the cache animation to be visible, the selection must include at least some of the originally animated vertices.
Specifies how playback occurs:
For example, if you record a cache from frames 0 to 100 and then want it to play back twice as fast forward and then in reverse, choose this option, turn on Auto Key, set the Frame parameter to 0.0 at frame 0, 100.0 at frame 50, and then back to 0.0 at frame 100. The function curve of this parameter in Track View shows how the cache is played back. Animating the Frame value lets you achieve unusual effects such as slowing a cache down over time, creating a ping-pong effect during playback, etc.
The frame number at which the cached animation starts playing back. Using decimal fractions lets you start at a sub-frame setting when using a Frame:Ticks time display. Available only when Playback Type is set to Custom Start or Custom Range. Default=0.0.
The frame number at which the cached animation starts playing back. Using decimal fractions lets you start at a sub-frame setting when using a Frame:Ticks time display. Available only when Playback Type is set to Custom Range. Default=0.0.
Lets you animate playback of the cache; for details, see Playback Graph, above.
Controls what gets loaded when the Playback Graph frame is out of the original recorded range.
Take an example in which the playback frame is set to 105, but the original cache was recorded over frames 0–100. With Clamp Graph on, the loaded frame will be 100. If it's off (the default), the cache will "wrap around" and load frame 5.
This lets you loop caches more easily. In the above example, you could simply have a two-key playback graph. The first key would be at frame 0 with a value of 0.0, and the second would be at frame 100 with a value of 100.0. You would then set the out-of-range type for the Frame parameter (Playback Frame in Track View) to Linear, and the cache would loop back smoothly to the beginning at frame 101.