What is different between Cache vs File vs Rop output node?

[kidsreturnjj]

Hi, I would like to get some advice about these three node, Cache, File and Rop output.

1. What is different between Cache vs File?

2. What is different between File vs Rop output node?

3. What is good for when I work for particle(emitter cache and spreading particle cache..etc)

[yongbin]

if you use rop output, then you will need file node for read the file.

or you can use file cache, it can do both read and write.

file cache is just convenient wrapper for ropoutput and file node. you can dive in to file cache node, then you see that there is rop output node and file node.

Edited August 20, 2013 by yongbin

[old school]

1. What is different between Cache vs File?

Both save geometry.

Both were designed to save geometry as you play forward, frame-by-frame.

Cache SOP saves geometry to system memory therefore very fast. Geometry goes away when you close the session.

File SOP saves geometry to disk therefore much slower than Cache SOP. Geometry is persistent.

2. What is different between File vs Rop output node?

Both save geometry to disk.

File SOP is designed to save geometry as you play forward.

Geometry ROP Output driver is designed to render geometry to disk over a specific frame range.

3. What is good for when I work for particle(emitter cache and spreading particle cache..etc)

It's up to you. Use both. Use the Cache SOP and it's reset button to refresh changes. Use the File SOP or Geometry ROP SOP to write the particle sequence to disk when you approve of the behaviour.

The Cache SOP can be used right after the POP network to cache the results so you can scrub back and forth and use point cloud look-ups, etc.

[yongbin]

ah, sorry I thought it is file cache.

[kidsreturnjj]

Thx so much, yongbin, oldschool for answers !

Now, I can understand these node more!

Thx again!!