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Cesar Montero
02-27-2008, 03:07 AM
I have been hunting down the following problem in the past month. I don't know the cause of if, just when it is caused. Light is leaking trough single sided polygons. into completely shadowed areas, even when just a single distant light is used along single sided surfaces ( subpatched, tesselated, planar, non-planar, etc).

This does not happen with such intensity in LW 8.5, but it is quite evident in LW 9. I would love for others to check it out, since I don't seem to find a solution on how to avoid it without the need of double sided surfaces, which cause other type of bugs on edges...

Lewis
02-27-2008, 05:33 AM
Can you make a scene where it's repeatable to test ? I'll happily test but i don't have free time to make it on my own :).

If is proven to be true/BUG NT needs to know about it ASAP since 9.5 is close.

wavemaster
02-27-2008, 05:35 AM
Are you using 9 or 9.3.1? I thought I remember a bug that was in 9 that caused this, but was fixed.

Cesar Montero
02-27-2008, 05:51 AM
Can you make a scene where it's repeatable to test ? I'll happily test but i don't have free time to make it on my own :).

If is proven to be true/BUG NT needs to know about it ASAP since 9.5 is close.

It is happening not so severly since long time ago. It happens in Lightwave 8.5, but it goes worse in LW 9.3.1

I currently don't have internet access at computer workstations. That is why I'm making this in windows paint. I would really appreciate it someone can make the test in lightwave.

Just add the previous setup, and set up a bump texture, crumple will do, any bump at any value will make the error ocurr. Maybe it is that most people render the lit areas, and that is why this error has been overseen. However, it becomes very evident when a scene is lit, and it needs to be baked. Then, the option of having double sided ( for solving this) becomes a problem too, since double sided surfaces don't bake correctly on small places. Therefore, this bug is a complete problem when you are dealing with productions involving lots of baking, in which you can't afford to use double sided polygons to "solve" the bug.

Cesar Montero
02-27-2008, 05:54 AM
Are you using 9 or 9.3.1? I thought I remember a bug that was in 9 that caused this, but was fixed.

I can replicate the error in LW 9.3.1 and LW 8.5 using default surface with a crumple texture to make the error go worse. Default settings for the crumple. Then set the camera in the opposite direction to the light, very much as an "eclipse." Increase the light intensity to something as 700%, and set the polygons to be smoothed. You will get lots of noise in the area which is supposed to be black.

I have been asking how to solve it to many LW guys, and they seem aware of the problem, but it seems to have been an "ongoing" problem. They solved it by using double-sided surfaces. However, using double sided surfaces in baking creates even more errors in the baking...such dilema is not very nice when you need to bake thousands of maps for a game.

wavemaster
02-27-2008, 06:02 AM
Is a bug I have ran into before and thought it was fixed, but it isnt...
Hope it is in 9.5!

Cesar Montero
02-27-2008, 06:05 AM
Is a bug I have ran into before and thought it was fixed, but it isnt...
Hope it is in 9.5!

Yeap, there you go, I get the same thing, and its a big problem.
Now, this time "oh, just use double sided" will not work.
Double sided creates errors with the baking camera.

So either bake things with these errors and correct them by hand
Or bake things with double sided and...correct them by hand?
Both ways are a problem when you are dealing with large amount of assets

Lewis
02-27-2008, 06:10 AM
wavemaster, post that scene :).

MooseDog
02-27-2008, 06:13 AM
hi cesar; judging from your illustration above, i tested the set-up with a simple ball, as you described, and sorry...no dice. it rendered jet black. i then tried it with a simple plane object, and...no dice. jet black. no artifacts. no g.i. just one light, 200%. tried all light types as well. 9.3.1 here. very curious what's happening over there.

wavemaster
02-27-2008, 06:16 AM
here...

Lewis
02-27-2008, 06:28 AM
Hmmm I don't see what's the difference between Double and Single sided surface here ' It renders SAME ???

wavemaster
02-27-2008, 06:31 AM
turn on rayshadows...

wavemaster
02-27-2008, 06:37 AM
Yeap, there you go, I get the same thing, and its a big problem.
Now, this time "oh, just use double sided" will not work.
Double sided creates errors with the baking camera.

So either bake things with these errors and correct them by hand
Or bake things with double sided and...correct them by hand?
Both ways are a problem when you are dealing with large amount of assets

What are you trying to bake, the final render or just a certain channel?

Cesar Montero
02-27-2008, 06:43 AM
hi cesar; judging from your illustration above, i tested the set-up with a simple ball, as you described, and sorry...no dice. it rendered jet black. i then tried it with a simple plane object, and...no dice. jet black. no artifacts. no g.i. just one light, 200%. tried all light types as well. 9.3.1 here. very curious what's happening over there.

Did you tried it with raytrace shadows?
I forgot to mention that in the description.

Cesar Montero
02-27-2008, 07:05 AM
Hmmm I don't see what's the difference between Double and Single sided surface here ' It renders SAME ???

With double sided surfaces light does not "leak" trough. Single sided surfaces with any bump WILL leak light in "the dark side" where light should not reach AT ALL.

Just give it a try: set a distant light, activate raytrace shadows. Put the default gray surface to a mesh which is enclosed ( ball, toroid, whatever ), activate smoothing, and render the "dark side" which light shouldn't reach...and you will see dotting. The more intensity, the more dotting.

In LW 8.5 the intensity of the error was less. It is more intense in LW 9.3.1, I'm not sure of previous builds, or new builds. I will have to check out at home.

Phil
02-27-2008, 07:22 AM
Email the bug description and scene to [email protected], then perhaps post the link to the bug report in this thread. The link will be sent in an email from NewTek when they receive your bug report.

Then the LW developers get to see it and anyone interested can follow the progress/nag the developers to fix it.

SecretSquirrel
02-27-2008, 07:45 AM
You have the crackle node into the bump channel on that surface, so maybe it's not light leaking through, but the bump mapping doing something odd.

Putting the crackle node into diffuse channel doesn't show the error.

Tried it with the material nodes, renders fine (into material channel)

Some of the other 3D procedurals when placed into the bump channel show the effect.

So it's something to do with bump mapping and not light leaking.

wavemaster
02-27-2008, 07:51 AM
It is a prob with the bump and has been around 4ever!

Cesar Montero
02-27-2008, 07:53 AM
You have the crackle node into the bump channel on that surface, so maybe it's not light leaking through, but the bump mapping doing something odd.

Putting the crackle node into diffuse channel doesn't show the error.

Tried it with the material nodes, renders fine (into material channel)

Some of the other 3D procedurals when placed into the bump channel show the effect.

So it's something to do with bump mapping and not light leaking.

Exactly :thumbsup:
I tried it with a texture map (JPG) in black and white for the bump, and it still happens. If at least I had that option I wouldn't worry...

Cesar Montero
02-27-2008, 07:57 AM
It is a prob with the bump and has been around 4ever!

That is what I have been hearing around, but it seems that in the past people just made "paint-overs" or used double sided surfaces to solve the problem. Both ways are not viable when I'm dealing with millions of polygons to be baked, or painted-over: a single object yes, lots of objects...might be a bit of a problem.

Cesar Montero
02-27-2008, 08:16 AM
Easy steps to replicate the bug in LW 8.5 and 9.3.1

Steps:

1) Open Layout

2) Load a ball, toroid, or any other enclosed mesh

3) Turn on Raytrace Shadows

4) Turn the light 180 degrees, opposite to the camera direction

5) Open up the light properties and set a high intensity value(100%-700%)

6) Position the object at the middle of both ( like in an eclipse, where the object is the moon)

7) Add a crumple or texture map into the bump channel.

8) Activate the smoothing of the surface, and let it be single sided

9) Press render

Result: You will get lots of noise in the area which is supposed to be black.

Observations: The higher the bump amplitude/opacity, the more noise areas it creates. The higher the intensity of the light, the more lit those areas are shown. The intensity of the error is less in Lightwve 8.5 than in recent versions of LW

gerardstrada
02-27-2008, 09:23 PM
Situation only appears with 3D Textures here. It's not present in layer system or Bump Layer node. So a solution is to switch to those procedurals or bake Bump channel first (an easy way is to input the bump nodal config into Diffuse Shading and use SBC). Load that bump image map into Bump Layer node (or layer system) and input this node in bump channel as always.



Gerardo

Wade
02-27-2008, 09:40 PM
Yep bump picks up the light when single sided - was thinking of posting myself - thanks for taking action. I will post some images and a scene in the in the morning.

Wade
02-27-2008, 09:43 PM
a brick r stone texture is good one to use to text with the grout...

jameswillmott
02-27-2008, 10:03 PM
The bump texture bends the surface normal towards the light source in places, thus even in shadow the bump texture shows up because LW thinks the surface is pointing at the light.

Lewis
02-28-2008, 01:31 AM
So is anyone sent BUG report to NewTek ?

Cesar Montero
02-28-2008, 02:35 AM
So is anyone sent BUG report to NewTek ?

I just did yesterday via mail bug report, and also via the bug system!
I'll keep a track on this one since I would really benefit from its "fix".
Never the less, its better for a whole group to speak, than a single person.
:thumbsup:

Cesar Montero
02-28-2008, 02:47 AM
Situation only appears with 3D Textures here. It's not present in layer system or Bump Layer node. So a solution is to switch to those procedurals or bake Bump channel first (an easy way is to input the bump nodal config into Diffuse Shading and use SBC). Load that bump image map into Bump Layer node (or layer system) and input this node in bump channel as always.



Gerardo

Mister G!
Hey man, I'm a bit lost in the explanation. Could you take a screen-capture or zip file of this? Maybe I'm not clearly understanding what you suggest. So far I get the same error even if I use an image on a bump node. arggggg...

Exception
02-28-2008, 02:59 AM
It's a bug in the bump mapping system.
I fogged it here (http://mail.google.com/mail/?ui=1&view=page&name=js&ver=yjawql5pzdvz), but so far no resolution yet.

g4dual
02-28-2008, 03:30 AM
Easy steps to replicate the bug in LW 8.5 and 9.3.1

Steps:

1) Open Layout

2) Load a ball, toroid, or any other enclosed mesh

3) Turn on Raytrace Shadows

4) Turn the light 180 degrees, opposite to the camera direction

5) Open up the light properties and set a high intensity value(100%-700%)

6) Position the object at the middle of both ( like in an eclipse, where the object is the moon)

7) Add a crumple or texture map into the bump channel.

8) Activate the smoothing of the surface, and let it be single sided

9) Press render

Result: You will get lots of noise in the area which is supposed to be black.

Observations: The higher the bump amplitude/opacity, the more noise areas it creates. The higher the intensity of the light, the more lit those areas are shown. The intensity of the error is less in Lightwve 8.5 than in recent versions of LW

mmm ... i think this is the scene ... but ...

pic rendered with LW 9.3.1

:help:

Cesar Montero
02-28-2008, 03:41 AM
It's a bug in the bump mapping system.
I fogged it here (http://mail.google.com/mail/?ui=1&view=page&name=js&ver=yjawql5pzdvz), but so far no resolution yet.

I click on your link and it sends me to gmail homepage.
Is this link correct?

Cesar Montero
02-28-2008, 03:46 AM
mmm ... i think this is the scene ... but ...

pic rendered with LW 9.3.1

:help:

That is actually little noise compared to what I get. I even get noise on areas where the surface is self-shadowing itself! Its not only on areas where the normal is facing away from the source...but in ALL self-shadowed areas.

So far I tried it with the normal bump system, the nodal bump system, plugin directly a bump map, etc. No combination gets trough it when I activate smooth on, and use single sided surfaces.

There is another bug for baking double sided polygons, but that is another story and another report.

Thomas M.
02-28-2008, 04:10 AM
I told BeeVee on the phone about this years ago. The normal flips and, voila, the light appears in the shadow areas. Unfortunately that one of the biggest weaknesses of the LW renderer. You always get this with water surfaces and procedurals if the sea tends to be "rough".

Cesar Montero
02-28-2008, 05:00 AM
I told BeeVee on the phone about this years ago. The normal flips and, voila, the light appears in the shadow areas. Unfortunately that one of the biggest weaknesses of the LW renderer. You always get this with water surfaces and procedurals if the sea tends to be "rough".

While it may be an inherited problem, result where not as bad as in the recent versions of LW. I tried with LW 8.5 and the error is there, but not to such amount. So I'm pulling my hairs here how to get around it if possible.

:stumped: :cursin:

Lewis
02-28-2008, 05:07 AM
Now when it's in BUG report it will be more in sight of DEV staff, The more reports the better :).

Wade
02-28-2008, 09:16 AM
Double sided blocks the light as it should single lets the bump pick the light in the scene when it should not... fairly simple to repeat.

Wade
02-28-2008, 09:19 AM
Make the surface double sided and the problem goes away - work around...

Exception
02-28-2008, 09:42 AM
Now when it's in BUG report it will be more in sight of DEV staff, The more reports the better :).


Been in there for ages. It's gathering dust.
It's also a repost of one already in the old-old bug system...

gerardstrada
02-28-2008, 03:35 PM
Mister G!
Hey man, I'm a bit lost in the explanation. Could you take a screen-capture or zip file of this? Maybe I'm not clearly understanding what you suggest. So far I get the same error even if I use an image on a bump node. arggggg...


Hola CÚsar,

At least here, this problem is not present in layer system. Please, take a look:

http://imagic.ddgenvivo.tv/forums/bump/bump0.png

This is a backlighted ball (700%), with crancle txture in bump channel. This is noticed even if light angle is not completely opposed to the object:

http://imagic.ddgenvivo.tv/forums/bump/bump45.png

So a viable solution - at least here - is to bake this texture as bump channel. In this case, I used the texture (it can be made with a nodal network as well) in diffuse shading input:

http://imagic.ddgenvivo.tv/forums/bump/direct.png

And baked it through SBC:

http://imagic.ddgenvivo.tv/forums/bump/SBC.png

We get something like this:

http://imagic.ddgenvivo.tv/forums/bump/UV.png

Later, we can use it into a layer node:

http://imagic.ddgenvivo.tv/forums/bump/layer.png

Result:

http://imagic.ddgenvivo.tv/forums/bump/bumplayer0.png

We can barelly see still a subtle trace of light in object border (like a rim light), but I can live with that and even find it realistic :)

http://imagic.ddgenvivo.tv/forums/bump/bumplayer45.png

You can see the test scene here (http://imagic.ddgenvivo.tv/forums/bump/bumpbug.rar).

Un Saludo!



Gerardo

Cesar Montero
02-28-2008, 03:44 PM
Thanks Gerardo!
That is a nice solution for procedural bump channels.
I'm however getting the error even on image maps.
I'll make a test and upload it.

gerardstrada
02-28-2008, 07:29 PM
At least here image bump maps works ok. Please, upload a simple scene to take a look. Maybe it's due to other variable as well and hopefully, we could find other solution.



Gerardo

Cesar Montero
03-05-2008, 03:42 AM
At least here image bump maps works ok. Please, upload a simple scene to take a look. Maybe it's due to other variable as well and hopefully, we could find other solution.
Gerardo

What version of LW are you using?

gerardstrada
03-05-2008, 01:42 PM
v9.3.1



Gerardo