rendering large images

[jamesdowling]

Hi!

I'm quoting for a job and potentially they want the image on a 17 meter billboard...I have never done large scale renders before and wondered if anyone had any experience/tips on doing it? Its an outdoor aerial image so at least its not anything internal.

I'm also assuming its going to be killer on ram so I will need to upgrade from 64gb to 128gb?

I know that you can use blow up area to render to split in into quarters but I think the final resolution would need to be 240945 pixels at 36 dpi (if i calculated it correctly) is that even possible in Max/Corona? I tried a test with some boxes and it was struggling with 10,000 pixels.

Thanks and any help is really appreciated!

[burnin]

First thing first... How are billboards made?
By pieces/tiles unless painted by hand :).
So just mimic the process to simplify and get your work done.

[Ink Visual]

From how close will the billboard will be looked at?
I mean, how much detail do you really need? For billboard print I have great experience  up-scaling my image using Gigapixel AI https://topazlabs.com/gigapixel-ai/.
I've compared image rendered at 10k and the one that I upscaled from 5k to 10k with AI and I was supprised how little difference there was between them. Try it, it has 30days free trial version.
It all depends whether your huge print will be looked at from close distance and then you need more detail in your textures, shaders etc, otherwise for far away viewing just a sharp clean image will do, small details won't be seen anyway.

[maru]

Check out these topics with various DPI/image size/medium size/viewing distance discussions:
https://forum.corona-renderer.com/index.php?topic=21437.msg136317#msg136317
https://forum.corona-renderer.com/index.php?topic=12342.msg79551#msg79551

[jamesdowling]

Thanks for the replies.

They want the image at A2 print but potentially might use is up to 17 meters which is a bit of a leap, I'm assuming at that size it will be at a distance as they have just said it would need to be 32 dpi. The job come through an agency so I unfortunately don't have any more info, I'm just trying to work out if its even possible for me to do.

 I had planned to do it in sections but wondered if there was any scripts/ programs that could help automate the process?

I will check out gigapixel though, that could be really helpful!

The links are great maru especially the distance to dpi chart. maybe I could get away with 12 dpi and upscaling.

[Juraj]

People have printed 20M long Billboards for past 40 years and even now we don't have more than 100mpx cameras (without pixel-shift). And those prints always looked perfect. So no reason for any nonsense gigapixel renderings.

Also, DPI doesn't have any correlation with PPI. You can print 500px large image with printer capable of 1200 DPI on whatever physical size you want, there is never any reason to go for parity between the image digital size and what the printer does to translate digital data into ink.
Dots are not pixels yet this myth keeps going on and on. Images printed in 600 DPI glossy magazines are never 600 PPI, every full-page photo would need to be 70 MP and these magazines looked already amazing back when digital cameras shot barely 5 MP :- ).

32 DPI is the highest their plotter will be able to print physically but you don't have to reach anywhere close to that with your input size.

Render 8k, use Gigapixel to give them up to 48k (largest magnification is 6X) if you feel like the guy from ad agency is unreasonable about DPI/PPI process himself and job done successfully.

[jamesdowling]

I did know about the dpi/ppi not relating but the 17 meter size was so massive its the only way I could try to come up with a render size, It looks like I was going to overkill it though so im glad I asked! I will stick to a 8k render and use gigapixel to upscale.

Thanks again everyone!

[Juraj]

You will be surprised how good it can be :- )

I lost a photo from DSLR I wanted to print, had to download compressed 2k version from Facebook...and voila...looked like from the DSLR.

It works on things it can identify, so renders that look like photos have very good success. Abstract things...not so much.

[jamesdowling]

Yea it looks great, never heard of it before but its getting added onto the shopping list!

[Njen]

Remember, most movies you see in the theatre are 2k. So if ~2000 pixels wide looks good on a huge movie screen, then you can gauge your quality settings accordingly.

[sprayer]

We was print  16m banner for exhibition stends but not from 3d render images.
17m 36DPI will be 24094 px.
You can render with stripes in backburner, also you may use AI upscaling program like Topaz A.I. Gigapixel it make good job without much loosing in quality

[jamesdowling]

Thanks for all the replies, its been super helpful :) I will have a look into rendering with stripes in backburner, never heard of it before but it sounds promising.

[James Vella]

I second Juraj on this, ive rendered plenty of billboards never over 8k render size (up to 30 meters wide) and look perfect from the ground.

[3dboomerang]

Guys, it's not all "see if it's ok" lol there are guidelines for this. Even damn printing companies get this wrong. It's really not that difficult.

You have PIXELS vs DPI + CM, no need to go into detail there, I assume you understand the basics.

So we'll focus on what targets need what DPI? This is what printing professinals even get wrong, which is stupifying to me but ok:

600DPI PRINTING BROCHURES or Magazines (A4 and smaller)
300DPI PRINTING POSTERS (A3 & A2)
150DPI PRINTING PLANS (A1 & A0)
90DPI / 72DPI ONLINE MEDIA USAGE (computer screens)
30 DPI PRINTING BANNERS or LARGE TARPS (> A0)

So now you know the DPI right? You're doing banners: 30DPI

Very low, why? 30 dots per inch means that you're printing something that will be watched from a distance, as in "meters" away and not "cm's" away like when you're looking at a magazine.
You'll be standing on the street, or driving by, so whatever printing company dares to ask for a 17meter banner, in for example, 150DPI, is uneducated on the topic. Unless there might be a specific reason, but I haven't come across that.

So 1700 cm on 30 DPI = ??? pixels >>> Open photoshop and put in the CM+DPI numbers, it will calculate the pixels for you by creating the document.

It should come to about 20K pixels in long side.

If you create an 8K render, and calculate it to 17m, you would get 12DPI. That's on the low side, but then again, it's a 17m Banner... That's really big, thus, I reckon 12DPI might be ok. If you wanna be on the safe side I'd go 20DPI= 13300 pixels (long side)

Hope it helps, GRTS

[James Vella]

If you create an 8K render, and calculate it to 17m, you would get 12DPI. That's on the low side, but then again, it's a 17m Banner... That's really big, thus, I reckon 12DPI might be ok. If you wanna be on the safe side I'd go 20DPI= 13300 pixels (long side)

Hope it helps, GRTS

Correct, usually 10dpi is quite standard for billboard sizes.

Theres also some good calculators online that can help you in this regard.

https://toolstud.io/photo/dpi.php?width=192&width_unit=inch&height=108&height_unit=inch&dpi=10&bleed=0&title=10%20dpi%20billboard