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View Full Version : Rendering super high res (30k pixels wide) - trick



Hieron
05-01-2010, 04:38 PM
Could've sworn I wrote this down before, but guess not so here goes as I think some may find it usefull:

I needed to render a shot for a 6 meters wide print at 150 dpi and thus needed about 30k pixels x10k rendered. LW doesn't want anything above 16k pixels dimensions and I wasn't really ready to go for a plugin at this short notice so I went for the shift camera which worked a treat and allows rendering over a renderfarm easily.

The workflow is:
1-Set up your scene normally
2-Increase the focal length of the camera x3. Thus you now only see 1/9the of the original shot. The exact middle, we will render all 9 pieces though.
3-Set the camera to shift camera go to the options panel and turn off "use cam pitch". You should now have the same shot as you had in step 2.
4-Now use the enveloppes to the horizontal and vertical pitch to "scan" the camera view over the 9 subframes you need. So go to -1, -1 at frame 1. -1, 0 at frame 2, -1,1 at frame 3, 0,-1 at frame 4 etc etc.
5-To allow blending, don't use 1 but 0,98. Leaving a 0,02 overlap which can be used to blend with in Pshop so no odd edges show up for whatever reason or plugin not playing along (who knows).
6-Render frame 1 to 9 :)

That way each frame is "only" 10k x 3.3k pixels which LW allows and is much easier to chew. If you need smaller subframes, don't use a x3 focal length but x5 for instance. It is not that hard to setup, and once done just save the camera and use it again later.

Unless I'm stating the completely obvious here :)

The scene with a camera set up that way for the x3 version:

84490

Resolutions and aspect ratios can be easily changed and it will all work fine. Check frame 0 for the full view and composition.

Chris S. (Fez)
05-01-2010, 05:00 PM
Interesting. Thanks for sharing.

There are a couple free scripts that automate a similar process. Split Render was one that worked particularly well that may or may not still be available...

At that size do you think you could get away with 100 dpi? At what size do you stop rendering 300 dpi?

kojean
05-01-2010, 11:26 PM
I think this tutorial by Thomas Mangold describes a similar method:

Tutorial on how to render high res without pain (http://www.newtek.com/forums/showthread.php?p=446873#post446873)


There are a couple free scripts that automate a similar process. Split Render was one that worked particularly well that may or may not still be available...
I was looking around for that old SplitRender plugin recently, but I couldn't find any working links. Does anyone happen to have a copy?

I think the latest might have been SplitRender 1.2 (Frenchwave-Splitrender.p) from this page:

frenchwave.org archive (http://web.archive.org/web/20050203182352/http://frenchwave.org/SplitRender/)

SplitRender Post from 2003 (http://www.newtek.com/forums/showthread.php?t=8506)

SplitRender Flay page (http://www.flay.com/GetDetail.cfm?ID=1641)

erikals
05-02-2010, 01:04 AM
just use limited region and render four smaller squares (4 times)
upperleft, upperright, lowerleft, lowerright

stitch these 4 together in PS

JonW
05-02-2010, 04:30 AM
What distance will the final image be viewed from?

It is surprising just how low the DPI is on some of these huge images. You would never even know unless you looked at them at a much closer distance than they were intended to be viewed from.

Hieron
05-02-2010, 06:44 AM
just use limited region and render four smaller squares (4 times)
upperleft, upperright, lowerleft, lowerright

stitch these 4 together in PS


That leaves room for accidents and mistakes, and is trickier to get a nice exact overlap. And doesn't work easily with a renderfarm..

And does that allow 30k pixels?



I think this tutorial by Thomas Mangold describes a similar method:

Tutorial on how to render high res without pain (http://www.newtek.com/forums/showthread.php?p=446873#post446873)

Unless I am missing something here, this is sort of the same idea but my suggestion is waay simpler. Let me quote some points in that .pdf:

17 steps and math:
-"use trigonometry to calculate the exact position on the Z-axis"
-"memorize the angle"
-"Get the tangent"
-"Get the reciprocal"
-"this is the exact position of the lens plane"
-"all numbers are only examples" (mine is universal)

Sure, the resulting idea is the same "moving the backplane" but mine is easier and is universal, numbers transfer to any project. Heck you could just "load item from scene" on that camera in the scene and never worry about how it is setup and just make frame 0 the view you want and let it render 1 to 8.

I guess Shift Camera came later than Advanced Camera, otherwise Thomas would surely have used the suggestion I did.



What distance will the final image be viewed from?

It is surprising just how low the DPI is on some of these huge images. You would never even know unless you looked at them at a much closer distance than they were intended to be viewed from.

Pretty close by.

This is not a banner or anything, it is a huge render of an area that people will stand at <1 meter from if they want (and did). I agree that (alot) lower resolution is fine when people will only see the whole for instance, but here people walk right up to it to point at their own office building etc.

I tested DPI requirements by printing (at real size ofcourse) on A3 and checking that.