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View Full Version : Lighting and Shadow Questions / Advice



Eyenovation
09-09-2003, 01:16 AM
Trying still to learn LW. Thanks to all those who have been very helpful.

Given my knowledge of the program is limited, I am just working with simple spheres and lighting, etc.

I am trying to go for photo realism as much as possible, as this will be the medium in which I work with.

Here is my latest attempt:

http://www.eyenovation.com/forums/3d/wrong.jpg

As you can see, it's NOT good. :(

I don't understand how I am getting the nasty aliasing on the ball? Is it my lighting? Is it my material selection?

Also, the shadowing is giving me a problem. I read in the last thread about selecting a different type, but I didn't see where I could:

http://www.eyenovation.com/forums/3d/shadowmap.jpg

It doesn't appear to be selectable? Am I doing something wrong?

http://www.eyenovation.com/forums/3d/scene_001.zip

Here is the scene, and the objects.
If anyone has any guidance, I sure would appreciated it.

southparx
09-09-2003, 02:02 AM
about the aliasing... i'm not really sure what causes that but maybe the reflection setting is too high (that makes that obvious grey reflection)

to make the shadow falloff, i think the type of light u use matters a lot, try using an "area light", it's much slower than others in complex scene, but if u place the light correctly u should be able to get nice soft shadow.

-in "light properties"
if you want to change the shadow type from raytrace to shadow map, the only way to get that is from changing the light type to "spotlight"... then on the "shadow type" hold and wait till the menu pops out, choose "shadow map", then change the fuziness and the other one above it (i think it's resolution if i'm not mistaken... i know it's the 500 value at default). feel free to play around with it, i almost always start with 1024 and fuziness of 5 rightaway (but depending on the scene though) but for me it's quite the good values to start.

yeah i think the reflection from the ground plane is too much, try lowering it and put a reflection blur (if you want)... to get this, go to your "surface editor" or press "Ctrl+F3" then click on your "ground" from the list at the left, then choose the "environment tab" (the one at the right most), there on this tab you can set reflection blur, refraction blur, change the reflection type to others like on that is very useful is "spherical map"... that means no ray trace reflection = faster rendering time.

hmm i remember there is one really useful surfacing/lighting/rendering tutorial in NT's tuts section, it's by Van... something... read that and i think you'll get through lots of the basics...

good luck take care

southparx
09-09-2003, 02:25 AM
oh i forgot this very userful tips when using "area lights", in your "light properties" window, click on the "Global Illumination" on the above there,
and in there click on "shading noise reduction" and set ambient intensity to 0% (get the habit of setting ambient to 0 in every case, except when u wanna use radiosity), then when shading noise reduction is on, u can try lowering the area light quality and combined with "medium" antialiasing, u'll might get better and faster result...(it works like this: whenever one antialiasing pass performed, shading noise will be recalculated and added to the rendering, so lowering area light quality, turning shading noise on and setting higher antialiasing is one way better than having higher area light quality and all those off)

hope the trick helps... and hope i say it clear enough

Zafar Iqbal
09-09-2003, 03:44 AM
http://www.digital-ray.dk/scene_001_redone.zip

I took a look at your stuff, and altered a few things:

Aliasing: It was caused because your Adaptive Sampling threshold was too high - i turned it off and lowered Anti-Alias level to Enhanced Low - You dont need 17 passes (btw: you dont have to turn off anti-aliasing when rendering with any of the Enhanced Anti-Alias settings).

Falloff shadow: I changed your lightsource to Spotlight, gave it a large cone and fallof size and turned on Shadowmap. Take a look from the Light view - if you look carefully you will notice a dotted box surrounding the ball. The size is adjustable (Map Angle), and i changed it manually (normally it has same size as the cone), because that will give better quality without having to crank the shadowmap size too much up. You can alter the shadowmap falloff by adjusting Shadow Fuzziness.

I also brighten the shadow slightly and gave it a red color - its barely noticable. But i dont think that would benefit you since it looks like you are using an older veriosn of Lightwave :)

Your objects didn't have any surface, so i quickly made some.

Hope this was helpful...

http://www.digital-ray.dk/ball.jpg

Zafar Iqbal
09-09-2003, 04:16 AM
BTW: http://www.presetcentral.com has alot of presets for surfaces and other stuff... worth checking out.

Eyenovation
09-09-2003, 07:46 PM
http://www.eyenovation.com/forums/3d/balls.jpg

I think I'm getting it!!
Thanks.
;)

Zafar Iqbal
09-09-2003, 08:56 PM
Sounds good :)

I would like to point out a "flaw" in your latest rendering just so you are aware of it some other time - take a look at the top right shadow. Notice how it ends - like it had been cut. This has to do with the Map Angle that i mentioned earlier (the dotted box when looking through light view). Just increase it's angle and you're set.