Odd Resolution Issue

[John Ferris]

Roy/All,

Rendering a front elevation for a job sign...needs to be at high resolution.

I did test renders at 24"x12" at 150 dpi. All looked good.

Went for final 24"x12" at 600 dpi and was oddly colored (1-600.jpg attached).

Dropped down to 24"x12" at 300 dpi and was dark (2-300.jpg attached).

Finally went back to 24"x12" at 150 dpi and it looked normal (3-150 dpi attached).

The attached 1-600.jpg was reduced in size in order to attach (not sure if the 5mb limit is per file or total...i went with per file...may need to do over if too big).

All of the renders ran at least 6 passes.

All of the renders setting were the same except for the resolution.

Anyone ever experience this? I haven't....can't render at high resolution?

Using AccuRender 1.0.348, Windows 8.1 64 bit, i7-4790 @ 3.60 GHz, 16 GB RAM, NVIDIA GeForce GTX 745.

Thanks for your help...

John

[Roy Hirshkowitz]

There are no theoretical limits as far as I know.  You are rendering a whopping 124 million pixels which I wouldn't recommend just for sanity's sake-- but it should work.  My guess is it has more to do with the orthographic projection causing precision problems.  There won't be much you can do about this.  You can check by rendering a more ordinary perspective and seeing if it fails as well.  You may be able to simulate what you need by using a perspective with a long lens (this may trigger precision problems as well since the eye will need to be placed far from the model).  If it's what I suspect it is, any help you can give the thing by allowing the eye point to be closer to the model would be a good idea.

If the problem is the ultra-high res somehow-- sometimes rendering at a reasonable resolution and upsampling in photoshop gives adequate results.  Sign are typically viewed from further away so the added benefit of ultra-high res is often not worth the effort. 

[John Ferris]

Thanks for the prompt reply Roy....Always appreciate coming here for help.

I had considered the ortho to be the issue - I'll either set up a similar view with a distant camera or will just go with the lower res and upsize post render...and save some sanity.

Thanks Roy...

John

[Peter Milner]

I had a similar problem a few months ago using the render farm software. The images came out almost black.

Roy found the problem and fixed it in an update.

I was only rendering a measly 58.5 million pixels.

[John Ferris]

Then maybe I need an update! Need to take a look...

Thanks Peter...

John

[Roy Hirshkowitz]

I'll look, but my recollection was that your issue was image editor related.  These are being saved directly to jpg. This may be a different problem so an update is unlikely to help.

[John Ferris]

10-4...Thanks again Roy...and Peter.

I'll give an update later after I try my options.

John

[John Ferris]

A few observations/questions:

See attached images/image names for comparison.

All settings remained the same except for the "Density" (DPI).

"X" was set to 30 and "Y" was set to 9; Lighting didn't change; Number of passes didn't change (except for one that went to 11).

Render Setting                                Image Outcome

9”X30”-10 PASSES-75 DPI              18.75”X5.63”-120 DPI

9”X30”-10 PASSES-150 DPI            37.5”X11.125”-120 DPI

9”X30”-11 PASSES-300 DPI            75”X22.5”-120 DPI

9”X30”-11 PASSES-600 DPI            150”X45”-120 DPI

Resized the attached images to the original intended outcome.

What's going on with the colors and brightness...and image size outcome?

Thanks for your thoughts...

John

[John Ferris]

Last file attached...had to reduce size.

[Roy Hirshkowitz]

The tone operator will be very fidgety at a low number of passes-- it normally takes a hundred or so for things to settle down.  Obviously something went very wrong at 600 DPI-- a whopping resolution of 5400 x 18000-- or more than 97 million pixels.

[John Ferris]

Thanks Roy...Guess we just need to let them run as long as time allows.

The high resolution one came about for a job sign and groundbreaking presentation boards need. We ended up just using 150 dpi at around 40 passes - worked out well. Mounted boards were 120"x40".

Thanks again,

John

[Roy Hirshkowitz]

Glad to hear it-- the 6 million pixels or so which this gave you should work-- provided people aren't too close to the sign.