muddy imap after merging

[powerandrubber]

I precalculated an imap in 2 segements, frames 0-500 and 501-1000. When I merge the 2 imaps the rendered result comes out muddy compared to rendering with the individual imaps. Notice how much smoother the first image is. Is there any fix for this?

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[powerandrubber]

Also there is a big difference in darkness.

[natty]

mmm ....are you sure you have kept identical settings for both imap calcs? ... the quailty looks totaly different? one seems to have more gi than the other? very odd. Did you render these on the same machines? with the same vray version? Not being funny but but the right hand image looks a lot lighter then to very top image? ... is it the same image? doesnt look like it.

[powerandrubber]

I don't know what's going on. I did another test and the merged version comes out lighter than the individual. I either made a mistake with settings or something happened with the file from crashing every other minute or there is and issue with merging imaps. Apparently no one else has had issues with merging imaps?

[natty]

Your setting do look different from form the 2 images, how are you saving your imaps? ... can you do a screen shot of your settings? ...

[vlado]

If you rendered these on two different machines, are you sure they render the same thing? Might the old "," vs "." setting issue. Also, which V-Ray version is that?

Best regards,
Vlado

[powerandrubber]

I thought of one possible issue looking at file sizes. I rendered the LC (secondary bounces, world scale flythrough) at the same time I rendered the imap for the first segment and set the LC to save to a vrlmap. For the second segment I set secondary bounces to none since the LC had already calculated. For final rendering I set both the imap and LC to from file. Could the LC have saved twice, once with the first segment imap and the saved vrlmap? I've been reading lately about LC saving with imap and don't understand how that works so maybe the LC is being doubled in the first segment? Looking at the imap file sizes, the first segment is a lot bigger (144mb) than the second (72mb). The vrlmap is 119mb and contains animation beyond the second segment since I was going to do a 3rd segment if time allowed so the numbers kinda add up.

Imap settings: High Animation preset, incremental add, every 25th frame
LC settings: subd 3000, sample size 2", scale world, mode flythrough

[natty]

hi

the light Data from the Lightcache will be saved within the irr map ... so set the secondary to none when you render from file.

[powerandrubber]

Ok I think I see. So when I merge imaps, the LC data inside the first segment (which was calculated for the entire animation) will be contained in the new merged file? I really appreciate the help, thanks!

So if I want to calculate and save imap and LC seperatly using backburner I should

a.) send first job with primary and secondary bounces set to LC with auto save in the LC settings
b.) send second job with primary bounces set to imap and secondary to none with auto save in the imap settings
c.) repeat for all segments
d.) merge imaps
e.) send last job to render with primary imap from (merged) file and secondary LC from file

[CXStudios]

From my understanding LC and IRMap calculations for animations can not be sent thru backburner... or was that just DR?

I follow these steps: ( I hope you're way is correct, that will really speed things up)

a) Render LC (set 1st and 2nd) one frame set to Fly-through
b) Set LC 2nd with LC cache loaded from saved file, render IRMap 1st set to Fly-through and every nth frame (I usually do every 5th frame)
c) Backburner render every frame with IRMap from saved file, and LC from saved file

I don't bring backburner into the sequence until all the GI maps our processed.

I also create individual map for each segment, not really sure why you would need to merge them, unless you're going thru the same area.... I'd still render new anyway IMO