lighting

[Noah Kadner]

Post some stills- that would help immensely. If you don’t have a site, just use

https://www.photobucket.com/

then post links to your uploaded images.

-Noah

[Bryan Richards]

Will do. Ill finish some of the modelling and make sure all the exact materials are assigned as a few are currently causeing too much reflectance so say late Sunday GMT+0 mid Monday, i should have some images posted. They dont look too bad, i know i can take them one step further though

watch this space 🙂

Cheers

[Adam Trachtenberg]

Critical question: are you using GI or strictly Cinema lights?

[Bryan Richards]

currently strictly cinema lighting,, i am however unfamiliar with what differnce O GL will make, there are just so many settings. its hard to find out what they all do because it can prolonge the render times so much you can be testing the options out your whole life :). I understand 9.5 is quicker at Caustics and Radiosity
Im away Saturday but will be attempting the lighting again on Sun evening. with images to put u in the picture. Thanks for the interest folks

Bryan Richards

[Bryan Richards]

i said i was going to post some images to a standard i couldnt improve because im lacking the knowledge of lighting. However ive been rendering all day to find a different problem.

settings

res @ 800×600
anti analising @ geometry
transparency @ with refraction
refection/shadows @ all

radiosity enabled.. strength+accuracy @ 70%
prepass size at 1/4 (currently stuck at about 75% the way through (will refer to this point later))
Diffuse depth @ 3
Stoch samples @ 200
res 3-70
solution saved
and ideentical noise dist @ true

the rest are set to true, if not mentioned they are flase or value left at default

Auto light
Textures
Cancel if text error
blurry effects
Volumetric lighting

Here is something which is too dark http://www.365.cx/bryan (if its not there then try again in a sec.. currently putting it on) . I want to know how to light up the inside but create a very bright out side area as if the Sun was very intense pushing streaks of light through onto the tiles, and lighting the inside up to a manageable realistic level.

This image I used the above settings with only one spot light @200% brightness shining down at approx 45 degree and guessed with the volumetric part of the spot light creating a convex volumetric cone (design view) which finished in the middle of the corridor which u can see,,,,, not sure what this does exactly, not sure if the whole room should be inside the spot light volume, or not?
Right, the next thing I have done to try and improve the situation was to shine another spot light @ 100% brightness from behind the camera and down the camera (horizontal plane) as to brighten up the inside.

This has killed the rendering times!
Im not sure if the render has stopped (maybe ran out of memory and exponentially slowing) or if it really is taking over two hours to draw 1 line of pixels. (my render is at 75% of its prepass and does not seam to want to continue. Do I wait, or has it died? It seams the extra light has created big problems

Comp spec

AMD XP64 +3800
1Gig Duel channel Ram
ATI XT850XTPE (think its T, could be X something else)
ATI chipset MB
that

[Bryan Richards]

its confirmed that the rendering was taking a very long time and it hadnt crashed. 1 pixel line on the preview was well over an hour. this is too long for me.

[Adam Trachtenberg]

Well, GI rendering is actually quite a tricky business. First–bad idea to use volumetric lights with GI. If you need that effect try to render the GI pass separately and composite, or fake it in post. Second, give your glass objects compositing tags and disable “Seen by GI”, and go to your glass material’s illumination tab and disable “generate/receive GI”.

Another problem is that there’s too much disparity between your GI Min/Max settings. Typically you want the Max number to be no more than 10x the Min number, and usually around 5x. If there’s too much disparity it forces the GI engine to do too much calculation.

As far as the the too-dark shadow areas, I suggest you increase the brightness of your sun light substantially–something like 500% brightness instead of 200%. That will blow out the directly lit areas, which is actually realistic for photographic images, but if you want to preserve the highlights you can use the color mapping effect. Actually that effect can also brighten up your shadow areas. Very useful.

Regarding the shadow aliasing, that’s a side effect of using raytraced shadows (hard or area). What you might want to do is set general AA setings to Best, 1×1, and give compositing tags to anything receiving shadows with higher settings.

So, I hope that’s at least a good start. 🙂

[Bryan Richards]

Some new stuff for me there 🙂
what do compositing tags actually do? and u mention to tag them to anything receiving shadows with higher settings. Not too sure on which settings your refering to there.

Ive noticed a drastic increase in rendering times here. Set this up along with a few other renders to sleep on not realising it was going to be so fast. shall have to stay up now. will post all these slightly different lighting renders for u all to see when im done.

second to this improving performance i changed a glass wall (quick archicad curtain wall construction) to a Cinema Plane. The archicad wall imports 6 separate planes which when materialised to glass creates a lot more internal radiosity calculations. The single plane sorted that!

thanks for the help again. watch this space for the link coming soon

🙂

[Adam Trachtenberg]

[Bryan Richards] “what do compositing tags actually do? and u mention to tag them to anything receiving shadows with higher settings. Not too sure on which settings your refering to there.”

Compositing tags provide for individualized render settings. In this case I was suggesting enabling the comp tag’s anti-aliasing function and selecting a stronger AA setting than the global AA I suggested (1×1).

One thing to be aware of is that Cinema lets you choose a higher AA setting for an object, using the comp tag, but it *won’t* let you choose a setting that’s lower than the global AA setting.

Other handy things the comp tag provides:

* per-object GI accuracy settings–can be very helpful for eliminating artifacts by using higher GI accuracy locally on difficult objects, e.g., ceilings and walls. Can also be useful for setting *lower* GI accuracy for appropriate objects, e.g., smallish, high-poly items.

* compositing background function–useful for creating perfectly white floors that still show object shadows, and for compositing in general 🙂

* object ID: allows you to create object-specific alpha mattes by assigning an ID # and then referencing the ID when you add object buffers in the render>multi-pass options;

* provides unrealistic but very useful ways to optimize your scenes, by, e.g., preventing individual objects from casting shadows, being seen by reflections/refraction, etc.

[Bryan Richards]

Youve given me some new direction here, appreciated.

Progress report:

volumetric lighting taken out.
composite tags added to the glass and all previous GL options edited on the tag and Banji

differences. Image is looking a tiny bit richer in colour. Only have the top half so far. rendering what was thought to be quicker on the prepass turned out to be a lot slower. 5hrs down the line we are about 45% the way through. Ill let it play and shall post

Even though my handin is tomorrow im determined to perfect this at a later date :0]

cheers Bry