Hi,
Once the files have been renderd out of MAX as an RPF image sequence, you only have access to the channels you chose to render out of 3DSMAX.
Bringing an image into combustion as an RPF gives you access to the channels you rendered out with the file. These channels includes the z-depth, material IDs and Object IDS........
You can use these channels to tweek the rendered images in combustion....
You can add particle emitters from combustion on a seperate layer and using the Z-buffer channel from the RPF, you could blend the layer of particles in between your max particle spray..... You could also track the particle emiiter from combustion. What you cannot do is change the settings for the max particles because that has been rendered out as an image....
To make those changes you would have to go back to MAX and re-render the image files again ntil you are happy with the MAX output...
Splice...