Write "dataWindow" into EXR please

[ultrasonic]

Hey Guys!

I know the vrimg2exr supports writing the "dataWindow" into the EXR Header. It would be awesome to have that feature available in the standard exr writing process! Do you think this is easy to implement?

thx in advance
Oli

[instinct]

generally yes. In this specific case it only makes sense to a certain extend. When writing EXRs via the VFB they are tiled exrs as that was introduced to remove the need to keep the whole image (and assorted renderelements) in memory during renderig. As tiled exrs support arbitrarily writing buckets just like vrimg. In order to retrieve the dataWindow you'd prolly need to have it loaded. Maybe a somewhat clever implementation could figure it out without loading it completely by taking bucket offsets into account...dunno

Mind you not using Maya here but Max, but currently we post convert EXR to zip1 and scanline based.

Regards,
Thorsten

[ultrasonic]

Tile based solution:

check if any sample in the tile has ever hit something. If yes mark the tile "hasData". storing that information is not to memory consuming and you can compute an approximation of the datawindow ,which is much better than storing no information at all.

This would be really cool!

cheers
Oli

[vlado]

The problem with the data window is that V-Ray does not know what it is until the image rendering is complete; however the image is written while V-Ray is rendering - when the frame is complete it is already stored on disk, so it is not possible to modify the data window anymore. This might change in the future if we implement writing to scanline multichannel .exr files.

Best regards,
Vlado

[ultrasonic]

thx for that information vlado...so i think i am going to add a postrender process in our pipeline like instinct does...not the best way,but if there is no other option, then i'll have to stick with it.

thx
Oli