View Full Version : how to avoidd the color to bleed to much

02-14-2013, 11:08 AM
hello, again another question, i have reds walls and a white celling, with radiosity the white celling become red, but it's very red, is there a way in lightwave to avoid or to reduce this effect ??

02-14-2013, 12:06 PM
Not really, no... tbh, getting colour bleed like that is one of the things radiosity is for. Ur best option is the same as ud do in a real photography situation... post work to re-white balance the image.

02-14-2013, 02:59 PM
Hi Jerome,

What is the intensity of your Radiosity? Try lowering it...



02-14-2013, 03:49 PM
Or to get rid of it all you can use backdrop only radiosity. It's extremely fast and has a different look but in a lot of cases very useful. Lowering the intensity like Rob said is the easiest way if you don't want to post it out.....

02-14-2013, 04:14 PM
check this vid out >

02-14-2013, 05:11 PM
to avoid, separate red parts from whites into a different object/layer and in object properties turn off radiosity...

02-14-2013, 06:40 PM
Put in a carpet and hang some paintings on the walls. Add a few plants. :)

Wouldn't lower diffuse and falloff'ed light reduce the bleed?

02-14-2013, 08:34 PM
check this vid out >

Brill :thumbsup:

02-14-2013, 11:45 PM
thanks all for the reply, it was exacly what i am looking for.

02-15-2013, 02:19 PM
Kray renderer has this option for surfaces, to lower the color bleeding. It's usefull for colored walls or floors to prevent the room to be too colored

02-16-2013, 07:10 AM
saw this thread too late - yes you can easily control bleed with spotinfo node.
I use spotinfo also to limit per-surface reflections, refractions and so on, very useful to optimize rendertimes.


02-16-2013, 08:11 AM
Pavlov, can I be a bit cheeky and ask if you could do quick screen grab of your nodes setup use on reflection/retractions? (Sorry, a little off topic!)

02-16-2013, 08:21 AM
To be honest, the simplest 'fix' for this is to use Linear Colour work-flow. Go into Colour-space settings and select the 'srgb' preset, and then welcome to the wonderful world of Linear Colour Work-flow :D Using the old-fi method of srgb colours and linear lighting makes Lightwave oversaturate colour bouncing. I use quite bold colours in my images, and I don't get much colour bleed, except where very strong lights are placed next to coloured objects, which is how it should be happening.

I go into some of this stuff in my tutorial for 3DW http://www.3dworldmag.com/2012/08/23/build-surfaces-in-lightwave/

Also Check out Matt's videos on the subject

You'll also find you get MUCH better interior lighting with this technique, much more consistently!

02-16-2013, 08:27 AM
raw-m Check out my tutorial, I go into that as well, using the 'Schlicks approximation node' developed by DB&W. I plan on doing a small tutorial on how to use that to get render times down, and optimise your surfacing. I asked Michael to develop it to help speed up /simplify surfacing using the technique of stopping the surfaces having reflectivity during the radiosity prepass.

02-16-2013, 10:17 AM
sure, here are both setups.
In these setups:
- limited bounce follows the gradient up to second bounce, then value is 0 from third bounce on. You can just do the same in transparency.
- bleed lowers saturation to 0.5 after bounce 0 (so, everywhere).


02-16-2013, 12:43 PM
Blimey, that's clever. Thanks for sharing, guys.

11-03-2013, 03:36 AM
This thread is exactly what I need for a small project, but unfortunately Pavlov's tips aren't working for me...no idea why though, but I am a complete noob as far as the nodes go. Tobian tutorial, either does not exist anymore on 3D world, or I can't access it for some reason :(.

Is there any other way to control bleed on surface? Lowered ceiling is in question. I have tried everything that came to my mind, and no result was remotely satisfactory.

Sigh, this is one of those things that Lightwave rendering engine is missing sorely for realistic radiosity interiors.

11-03-2013, 04:19 AM
If you want it to work you have to use the node on the surface that you don't want radiosity from....

Not the way you would think. Don't put it on the ceiling.... put it on the floor. :)

11-03-2013, 04:36 AM
Ouch...I told You I was a noob :) Thanks XswampyX, will give it a shot.

11-11-2013, 01:47 AM
I finally managed to get bleed under control to some degree, thanks to tips in this post, but was still not satisfied with the result :( If only there was a way to get only 50% of bleed from that first bounce, as it seems that is where the most of bleed is coming from.

For anyone here using and understanding the nodes, can it be done? If it can, would it be possible to post Your .pst file, It would mean much for folks not dealing with nodes yet. Thanks.

11-11-2013, 04:40 AM
I add a new layer with flat geometry, slightly above the floor, with a white/grey surface, make it unseen by camera and then you can control the color of the bounce by changing the color of this object. The floor is usually the most problematic because lots of rugs tend to be dark and or highly saturated colors. Add a little dissolve ( 1% is fine) to the that layer or you might get splotches from radiosity not going through it.

11-11-2013, 10:59 AM
Hmm sounds a bit too overcomplicated Danner! :)

It's quite simple really... Just do as in the attached. This should desaturate any colour or texture after the initial ray (camera). The only problem will be is if you see this interior through glass.

Seriously though, the fastest way to control your bounce bleed is to go to your display options in Layout (d) go to the CS tab, and select 'sRGB' on the quick presets dropdown. The main reason you get so much sautration in your bounce is because inputs and textures come in as sRGB colour, which means they are over-saturated. Using this preset de-gamma's the inputs for colour bouncing.

11-11-2013, 11:32 AM
Ok just as a quick example..

Same scene (no nodal tricks) Lit using the default (old style) Linear and the sRGB method...

First thing you'll notice is that more of the fill from the environment is more prominent and the orange saturation is less. You will also notice you get more fill light from bounce period.. This is because the lighting and colour calculations are more correct under the sRGB model.

Note, you will need to disable 'draft mode' in VPR to see this properly, or wait for your final render.

11-11-2013, 11:49 AM
Just to add to this, here's the light cranked up to 300%

You'll notice a couple of more things.

1) The colour has actually shifted, to be more yellowish, on the floor, and the whites are super-blown-out.

2) In the sRGB this is not nearly so bad, and it's still not as saturated, even though there's 300% bright light. You can also notice some modelling on the white parts, even though they are brightly lit.

3) the light bounce is still more satisfying and less orangey in the sRGB one, and there's more contribution from the external blue sky (which is more correct).

I also did one with a sun set to 600%...

You will notice that in the linear version the floor is a rather violent yellow and the whole room is pretty much orange.

The sRGB version is also still more or less the same orange, just more brightly lit, and the room is still not completely overpowered by it.

11-11-2013, 12:48 PM
Heck, I love these colorful GI renders.

11-11-2013, 02:31 PM
Hmm sounds a bit too overcomplicated Danner! :) ..

It's not. it is even node free! ;o) And it gives you the flexibility to adjust color and intensity to the bounce. Been using sRGB since it came out as a preset and even then sometimes my whites get more saturated than the client would like, I'm ok with it, but it's hard to explain to a client that their ceiling really is white, even tho it looks pink.

11-11-2013, 02:36 PM
Well a lot of that is to do with tonemapping too, tonemapping can help resolve issues of colour saturation and over-brights too.
You could get some very odd shadows by doing that, so I'd prefer to avoid it, but each to their own. It's not terribly hard to do this stuff, and we have compounds now, which can streamline it all ;)

11-12-2013, 01:03 AM
Thanks Tobian and Danner for the invaluable input, will put it to the test as soon as I can.

Oh and btw Tobian...fantastic work on Your site. I'm rarely on forums (job kills the free time), and just checked Your gallery.

I wish You could write up some tutorial for Interior lighting when You find the time :)

11-13-2013, 08:02 AM
The reason behind gettin thuis much color bleeding is becouse of the saturation of your shading. If your color will be less saturate the bleeding will be less.
Change the saturation of this red, desaturating, and problem solve!

11-14-2013, 03:22 AM
@inakito these are only exaggerated examples of the problem, however when doing interior shots Your clients pick colors, not You :) , so You can't desaturate the colors of their choice, be it on the walls, ceilings or furnishings.

11-14-2013, 06:08 PM
Ok, lets put it simple. Think as in photography, if you are taking a real picture of a super saturate surface you will try the best to make it not this saturate using methods such as sprading more the light along the surface, making direct lights not hitting straight on em, and so on...
Rendering is taking pictures, never forget that.
Treat your materials and shade em as if they were real... All the implementation on Lightwave brilliantly done about Linear Workflow super helps on that.
Obviously speaking about photoreal rendering techniques.
On non realistic rendering the treatment changes a lot.

11-15-2013, 04:50 AM
So did you get the nodal setup working ?
I use it daily to control bleed saturation and i can grant it works.


11-15-2013, 05:33 AM
I used it yes, but I'm not satisfied with the results completely, even if they are better than without it as I explained few posts above. I haven't tired yet sRGB approach or adding a false floor/ceiling as Tobian and Danner respectively suggested. When the surface that casts bleed is close to the surface that receives it, the nodal setup is unfortunately not all that effective.

11-15-2013, 05:43 AM
Hmm, then you did something wrong... because it does work... :-)

11-15-2013, 06:02 AM
It should be 100% effective at removing bleed... if you look at the youtube video example by Bryphi, there was zero bleed on the ceiling after it was set up. Obviously that looks unrealistic, but it does work! :D

11-15-2013, 06:05 AM
Hmm, then you did something wrong... because it does work... :-)

If You are talking about de-saturate node setup that You posted few days ago, I haven't tried than one. I was talking about those node setups up in the topic, but I do not doubt that this one will work. Will try it when I get back to the job in question for sure.

11-15-2013, 06:51 AM
raw-m Check out my tutorial, I go into that as well, using the 'Schlicks approximation node' developed by DB&W. I plan on doing a small tutorial on how to use that to get render times down, and optimise your surfacing. I asked Michael to develop it to help speed up /simplify surfacing using the technique of stopping the surfaces having reflectivity during the radiosity prepass.

Any chance of briefly describing the way you use that node Tobian? On any given surface where does it sit in the node structure?

11-15-2013, 10:37 AM
Basically the setup tells the color to desaturate after bounce zero.
You have to set saturation to zero, if you dont wat to get bleed.
It should work in any situation, if it doesnt happen please show your setup and we'll hammer it for sure :)
Remember you're acting on the amount of saturation which material adds to light's color, but if you have a wrong light color, the setup wont handle it.


11-15-2013, 04:04 PM
Ok here's the test scene I made (yes yes bask in my amazing modelmaking :) You can see the render with the desaturation effect. I also put in a Schlicks node for you DJ, so you can se how I use it place of a typical Fresnel on the floor. I ramped up the sunlight, so you can really see the effect.

11-26-2013, 07:20 AM
The desaturate node works wonders...thank You Tobian...again :)

11-26-2013, 07:38 AM
Nice examples! What's that Blocker object doing, Tobian?

11-26-2013, 07:53 AM
LW often has issues with joins between sharp corners. I was getting tiny pixel light leaks, and because the environment and sun are really bright those bright pixels wouldn't clean. Putting in the blocker in helps stop it. also double sided does too.