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View Full Version : Lightwave - Shadow,Lighting and Exposure issues.



HolyMonkey-
02-13-2011, 05:28 AM
Hello,

I recently opened a thread regarding shadow issues, but I felt there were some more topics we could cover so that not only me but everyone who doens't have indept knowledge can learn from the pro's here. Lets get started =)

I've put up a render covering the topic I'd like to focus on.

----
Incase necesserary here are my scene specifics:

The Scene is lit with a single Directional Light, and very simple textures for the poles(Just Colors). Building Probe HDRI was used as texture environment to create the reflection in the Poles, aswell as the floor.

Render settings are Radiosity, AO, Directional Rays, Volumetric Radiosity.

100 Intensity, 4 Bounces, 150 RPE. Camera settings are basic.

http://img593.imageshack.us/img593/4394/newteksetup.jpg (http://img593.imageshack.us/i/newteksetup.jpg/)

Shadow, Lighting and Exposure.

Let's start with Shadow.

1. In the image you can see the shadows are very hard and crispy not soft and smooth or faded out as some prefer to have them.

This is obviously because of the directional light from a perspective position. There is an option to set the shadow fuzziness and quality manually in the light option, however this is grayed out. Do you know how to activate it? The Shadowmap in the render globals is set to activated.

If you have any experience when it comes to messing around with shadows, perhaps how the different lights give of shadow effects or tips and tricks, or even a webtutorial. Please dont hesitate to post it here.

2. Lighting

This is a vast topic and kind of hard to narrow down. If we stick to the topic of lighting without any usage of HDRI image, a simple scene such as the one you see in the image above. Your lighting tips would be greatly appreciated. You prefer to use 3 point lighting? Single light? As always any tips tricks you learned that you feel is useful that you'd like to share?

How do you get around the issue of grainy shadows, or grainy lighted scene without adding in more light or raising the light strenght and creating a stronger exposure than necessary.

3. Exposure

A problem I sometimes encounter is unrealistic exposure such as the white spots coming off the pole as I marked of in the image (White Shadows).

What causes this, and more importantly how do you get rid of them?


Also someon with indept knowledge explaining these functions of LW's renderglobal.

Interpolated (IP) -
Volumetric Radiosity (VR)-
Directional Rays (DR) -

And least adaptive sampling. Explaining threshold and oversample.

I have a link for you to read if you're interested in rendering it's quite useful for alot of things especially rendering with HDRI, and light setups. Taken from newtek.

http://www.newtek.com/lightwave/tutorials/rendering/fullprecision/index.html

3DGFXStudios
02-13-2011, 05:46 AM
If you want to learn about radiosity you can read this guide. http://www.except.nl/lightwave/RadiosityGuide95/
But one thing is sure. You need to use more rays (RPE).

If you want nice and smooth and fast shadows you can use DP Infinite(found here http://dpont.pagesperso-orange.fr/main_en.htm) light of the dome light for example. You can also use area lights for more accurate results but they render slower. The distant light isn't a realistic light because if you move and object further away from the light the shadows won't get longer. It's just an angle. You can place it where ever you want but the location of the light doesn't affect the shadows.

Also I see that you didn't use any incidence angle gradients on your reflections and diffuse. You should. ;)

And if you render with HDRI you don't have to use lights.

HolyMonkey-
02-13-2011, 06:08 AM
Thank you so much for your reply, great help already!!

Care to go more into detail regarding incident angle gradient? I know how to use it just not the logic behind it.

Using a dome light creates a grainy effect on my render. Any idea to solve the shadow map issue?

The HDRI's I have are all free, but really small and poor quality. Is there any good ones out there that dont cost?

Cheers Thank you =)

3DGFXStudios
02-13-2011, 06:40 AM
You can get rid of the grain by upping the aa or reducing the angle. Reducing the angle will sharpen the shadows.

If you want nice HDRI's check this site: http://smartibl.com/sibl/index.html

About incidence angle reflection stuff: In real life surfaces reflect more if you look at them at a smaller angle. look at your coffee cup. The edges look like they reflect more light but the surface that is facing you at a 90 degree angle almost doesn't reflect at all.
You can read about it here:
http://en.wikipedia.org/wiki/Reflection_(physics)
http://en.wikipedia.org/wiki/Fresnel_equations

HolyMonkey-
02-13-2011, 07:25 AM
Thank you so much for the HDRI, and the reference. Also your example was great, and I understand some of the reflection. What I don't seem to completley grasp is how this applies down to the

| | <-- Gradient bar in the Incident Angle Layer.

If I understand it correctly adding a value of 0 in the middle of the bar will result 0 reflection at the front of the "coffee cup", although my results seem to differ slightly from the desired effect. I'll upload an image soon.

3DGFXStudios
02-13-2011, 08:55 AM
Here is how it works. (image) Left the old way. If you use that you should use an inverted gradient on the diffuse. In the nodal version you can reuse the gradient by adding a invert node. If you don't compensate the reflection with the diffuse gradient you'll get blown out reflections.

HolyMonkey-
02-13-2011, 10:37 AM
Thank you for your incident angle picture =)

Just tested out the HDRI method, and focusing on the information from the sites you provided.

I've only though added the Incident Angle classic way. Couldn't catch your image before now.

http://img823.imageshack.us/img823/1369/pictureza.jpg (http://img823.imageshack.us/i/pictureza.jpg/)

The image is pretty craptastic. The Scene is too dark, the car looks like plastic.

I've used the HDRI image shown in the back, following by Dome Light with 20Amb - 40 Strenght

The textures are simple as usual (guessing this is where the problem lies).

Any tip to get me headed in the right direction? Cheers


Scene Stats

Image World HDRI

50% Brightness
---
Red Paint for the car 90 Diffuse, 40 Spec,60Glow,40Refl with Incident classic.

RG

MC, Intensity 100, 40B, 300RVP,40,45,4,100,100


I tried some different HDRI's and upped light and brightness whatever, I just cant seem to get the realistic feel to it.

3DGFX thank you so much for your help so far. =)

nickdigital
02-13-2011, 10:40 AM
Check out Matt Gorner's sIBL tutorial. That might help too.
http://www.pixsim.co.uk/lightwave_video_tutorials.html

HolyMonkey-
02-13-2011, 10:50 AM
Update :
http://img717.imageshack.us/img717/5520/image01023012.jpg (http://img717.imageshack.us/i/image01023012.jpg/)

Added your way of adding incident angle. It still looks far from a good image, but theres also alot of improvement just by such a simple thing nice =)

Thank you for the tutorials nick! :)

3DGFXStudios
02-13-2011, 11:40 AM
The next one is a lot better. I think you did exactly the opposite in the first one ;)
Is see that your colors are pretty dark and saturated. If you are using lw 10 it is possible that your color space setting is wrong. The Sibl plugin has also a color space option. If you're using 9.6 make sure you have set it to sRGB.

Check this thread. I haven't read it myself but it think Matt explains it very well (like always) :D

http://newtek.com/forums/showthread.php?t=102397

If you save your renders in 32bit float like OpenEXR you can correct a lot in a compositing application like fusion, nuke or AE. Photoshop is also an option but I can't recommend it.

HolyMonkey-
02-13-2011, 11:03 PM
Hey, first of all thank you two so much for your help. I've seen the tutorials and they've been really helpful. Learned alot =)

http://img64.imageshack.us/img64/2926/gammaadjustment.jpg (http://img64.imageshack.us/i/gammaadjustment.jpg/)



As usual im left with a few questions :

Why wont it let me save the gamma adjustment from the viewer down to a image file? (Had to do a print screen)

I cant locate the option where you can set the standard gamma of your renders to common 2.2 which he talks about in his video "Yes, in the Image Processing Tab on the Effects panel, pull down on FP_Gamma, put your target gamma in there"

I cannot locate where to change the gamma value for the textures itself either. :(

Sorry if these questions are really stupid, I tried searching for them but I cant seem to find them.

Incase it matters the LW im using is 9,5.

Regarding the SBL plugin somehow I keep tellig myself I want to learn to do it the "old fashion way" and not relay on a plugin, is that just stupid of me not taking advantage of the technology? The plugin didnt seem to differ much aside from easy to use and having the rotation option of the image world easily handed to you.

On the site you provided regarding the directional light with a soft shadow, the plugin isn't there.

nickdigital
02-13-2011, 11:23 PM
This is the link to the light plug-in that 3DGFX was pointing to.
http://dpont.pagesperso-orange.fr/plugins/lights/Additional_Lights.html

As for the color space preferences I think that's a LW10 thing. You should also upgrade to 9.6 instead of staying on 9.5.

As for using sIBL it's all up to you. It's good to learn things but the plug-in is probably doing a lot that you might not be able to do by hand or just making things more efficient for you. You could always get the HDRI book that's mentioned in the video and that'll probably explain more of the nuts and bolts of what's going on.

HolyMonkey-
02-15-2011, 11:25 AM
Sorry or the delayed replay, going to upload a few pictures soon, just a few thing remains. The light plugin wont load.

"Plugin were not found or could nto be loaded"

I put it in the plugin folder, but yeah any idea what's wrnog there? hmm :help:

nickdigital
02-15-2011, 11:29 AM
Did you download the right version? 32 bit version won't on 64 bit LW and vice versa.

HolyMonkey-
02-16-2011, 11:07 AM
Did you download the right version? 32 bit version won't on 64 bit LW and vice versa.

haha, I thought my computer at home was a 32 bit.. Guess I was wrong =) Cheers,

http://img153.imageshack.us/img153/64/graphst.jpg (http://img153.imageshack.us/i/graphst.jpg/)

Here's a render for the first scene after your epic help =)

dwburman
02-17-2011, 09:23 AM
BTW the fuzziness setting is for Shadow Map (not raytraced) which are only available in Spotlights.

And before we had the dome light or the ability to add new light types, we had the spinning light trick (ftp://ftp.newtek.com/multimedia/movies/w3dw/spinlight.mov). :)

dee
02-17-2011, 10:00 AM
If you don't compensate the reflection with the diffuse gradient you'll get blown out reflections.

Exactly, keep in mind this simple formula: diffuse + reflection < 100. Use the Conductor node material for reflective surfaces which takes this formula into account.

HolyMonkey-
02-19-2011, 01:18 AM
Exactly, keep in mind this simple formula: diffuse + reflection < 100. Use the Conductor node material for reflective surfaces which takes this formula into account.

Thank you for your help, care to elaborate conductor node material?

I dont have indepth knowledge in LW this sounds confusing to me sorry =)

Assuming it's just a node option in the node editor? Haven't checked it out yet.

HolyMonkey-
02-20-2011, 04:22 AM
I used the knowledge u guys teached me and made a light bulb.

http://img710.imageshack.us/img710/9610/lightbulb01.jpg (http://img710.imageshack.us/i/lightbulb01.jpg/)

Obviously there's a few things wrong with this image, so what would you do to make it better? =)

I cant seem to figure it out 8~

Cheers!

dwburman
02-25-2011, 10:24 AM
Conductor is one of the material nodes. Just plug it into the Material input and turn up it's Specularity to get reflections.