Michael J. Brown Posted January 22, 2009 Share Posted January 22, 2009 One of the first things I noticed when I started using Vray is that rendering using the "Region" option (as opposed to "view") always yields different results. The tonal values are always off. Whereas with Mental Ray, you could always count on perfect matches when re-rendering just a region of a scene to patch in later using Photoshop. Is there a way to fix this so that the tonal values of the Region render always match the previously rendered "View" render? 1 Link to comment Share on other sites More sharing options...
aclub Posted January 22, 2009 Share Posted January 22, 2009 great question, I would love to know as well! Link to comment Share on other sites More sharing options...
BrianKitts Posted January 22, 2009 Share Posted January 22, 2009 that's odd. I patch render stuff all the time with vray and have never had an issue. Does this always occur for you or is it intermittent? are you using the max frame buffer or vray's? Link to comment Share on other sites More sharing options...
Michael J. Brown Posted January 22, 2009 Author Share Posted January 22, 2009 that's odd. I patch render stuff all the time with vray and have never had an issue. Does this always occur for you or is it intermittent? Every single time. are you using the max frame buffer or vray's? DOH! That must be it. I'm using max's. Link to comment Share on other sites More sharing options...
Starless Posted January 22, 2009 Share Posted January 22, 2009 Are you using light cache and irradience map? If you are the regions don't match because Vray calculates them for each individual render. If you want a perfect match you can save out your light cache and irradience map seperately and set Vray to load those in instead. Link to comment Share on other sites More sharing options...
BrianKitts Posted January 22, 2009 Share Posted January 22, 2009 Are you using light cache and irradience map? If you are the regions don't match because Vray calculates them for each individual render. If you want a perfect match you can save out your light cache and irradience map seperately and set Vray to load those in instead. I'm not sure that's completely necessary. Assuming you are rendering with the settings untouched from before, you should get the same pixel sampling result regardless of the initial region. It might be a slightly different calc, but not something that's blatantly visible. Quite often if I have rendered a full image and have a small spot that i want to patch. I will fix the geometry then go back and just patch render it. Assuming your patch doesn't make a huge impact on the GI calc around the object you should be able to slip it right in in photoshop. The exception would be if you have a big lighting change for instance changing a black wall to white you'd get more color bounce throughout the scene which would cause your region render to no longer blend in. In this case your better off re-rendering the whole shot, or expand your region render to give yourself a buffer zone around the change, render it out.... and then when you place it in photoshop take a large soft brush to feather/erase out the buffer zone and blend in the new region. Link to comment Share on other sites More sharing options...
Starless Posted January 22, 2009 Share Posted January 22, 2009 You're right Brian, I guess that is the extreme solution to that. I do a lot of furniture in white environment renders, and the buffer-with-feathered-brush is usually what I do for region rendered changes. Link to comment Share on other sites More sharing options...
Michael J. Brown Posted March 13, 2009 Author Share Posted March 13, 2009 (edited) I'm still not getting the results I need when rendering patches (using the Region render method). Using saved soutions is a useless option for me in this particular situation because of RAM. I know one popular option is to render and save the solutions at a lower res, then render at high res using the saved solutions. No dice here. My RAM keeps topping out regardless of whether it has to do pre-calc or not. I'm still running 32-bit and keep smacking head-first into that 3+gig RAM block wall whenever trying to render a 'large' interior image. Short of being able to get the images to run successfully at their desired resolution, I've settled on the compromise of 'strip' or region renders - to be pasted back together in post. BUT - I can never get my regions to match up lighting wise. Regardless of whether i'm saving (but not pulling from files) my Irradiance Map & Light Cache or having new maps built with each render (single frame mode). Can someone who never has this issue of mis-matching region renders PLEASE post screne shots of your Render Scene settings? I don't want to have to send my stuff out to a render farm just because my regions refuse to render with matching light values. And tryign to Photoshop the values to match perfectly when you've got 3 or 4 strips comprising one image is a loosing proposition. It'll rarely be perfect and undetectable. Thanks a ton. Edited March 13, 2009 by renderhaus Link to comment Share on other sites More sharing options...
BrianKitts Posted March 13, 2009 Share Posted March 13, 2009 Every scene needs different settings, so someone else posting their render settings isnt' going to help you. On the other hand if you post yours we might be able to give you suggestions on what to try to solve the problem. I find this problem of yours quite odd, as I could patch render an entire image in sections and it would all come out fine. So prehaps this is something you need to put up on the chaosgroup forums (or email them) so you can get a fix directly from the guys @ vray themselves. Link to comment Share on other sites More sharing options...
Michael J. Brown Posted March 13, 2009 Author Share Posted March 13, 2009 Thanks Brian. I'll try that. Link to comment Share on other sites More sharing options...
Michael J. Brown Posted March 17, 2009 Author Share Posted March 17, 2009 Well, I just (over the weekend) figured out why all my region renders kept coming out with different lighting. Or at least, I found out how NOT to have it happen. I've been using 1.5 SP1 here at work. SP1 has no VFB region capabilities. So even though I was rendering to the VFB, I was still using Max's render region. This weekend I finally got to use the new SP3 upgrade on my home system and discovered (much to my delight) region capabilities right within the VFB with no lighting variations between regions. WooHoo!:D Now, I;ve just gotta get my employer to update my machine at work. No wonder nobody else seemed to be having this issue. Nobody else here was still stuck on SP1. VFB region rendering was probably optional with SP2 too, wasn't it? Link to comment Share on other sites More sharing options...
BrianKitts Posted March 17, 2009 Share Posted March 17, 2009 VFB region rendering was probably optional with SP2 too, wasn't it? No, it was just added in SP3. But even without it, I still stand the only way you'd have that problem in SP2 is if you are using the max buffer instead of the vray frame buffer. Link to comment Share on other sites More sharing options...
dbibb Posted March 17, 2009 Share Posted March 17, 2009 What are you Light Cache settings? V-Ray will use proportionally less samples based on the size of the region, which can cause slight differences. Low subdivs will usually exacerbate the problem. When strip rendering, you should always pre render the LC. If you can't due to RAM, then you need to optimize your scene (reduce map sizes, use proxies, render via backburner instead of locally, etc..) There are lots of threads with tips on here and the chaosgroup forums. Link to comment Share on other sites More sharing options...
Michael J. Brown Posted March 17, 2009 Author Share Posted March 17, 2009 Unfortunately I've never rendered in SP2, only SP1 and SP3. But I do know that I've gotten the same (sporadic) render results using Max's buffer with V-Ray SP3 as with SP1. But when using the V-Ray buffer in SP3 all the stars seem to align. I'm just glad to have a solution. Even if it's a solution to an issue that most others didn't seem to be dealing with. Link to comment Share on other sites More sharing options...
Michael J. Brown Posted March 17, 2009 Author Share Posted March 17, 2009 What are you Light Cache settings? V-Ray will use proportionally less samples based on the size of the region, which can cause slight differences. Low subdivs will usually exacerbate the problem. I used to use a very low setting there - around 50. But someone here suggested bumping that up to between 1200 and 1600. I've upped it, but was still gettting variations in region renders (using Max's frame buffer or VFB) When strip rendering, you should always pre render the LC. If you can't due to RAM, then you need to optimize your scene (reduce map sizes, use proxies, render via backburner instead of locally, etc..) There are lots of threads with tips on here and the chaosgroup forums. Yep, I do the cache saves. And about 90% of my non wall/window/door/floor scene objects are already proxied. Thanks all. It seems VFB regions in SP3 has gotten me squared away nicely. Link to comment Share on other sites More sharing options...
Rachel Reichman Posted April 18, 2022 Share Posted April 18, 2022 Hi everyone Many years since this thread, I have now same problem. Strip region doesn't match. I am using Sketchup 2020 + Vray 5. Can you please help? Link to comment Share on other sites More sharing options...
Francisco Penaloza Posted May 9, 2022 Share Posted May 9, 2022 On 4/17/2022 at 11:58 PM, Rachel Reichman said: Hi everyone Many years since this thread, I have now same problem. Strip region doesn't match. I am using Sketchup 2020 + Vray 5. Can you please help? You need to change the Sketchup Viewport to show "safe frame" or match V Ray output image proportions. his can be done under V Ray window settings or using the Advance camera options in Sketchup. Link to comment Share on other sites More sharing options...
Kristijan Matasic Posted January 24 Share Posted January 24 It happens to me when I have the Exposure Value on Auto. Then it seems to take automatic EV only for that part, and it is of course different than the whole picture. Try with the same EV settings. ps I hope I understood the problem correctly Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now