Hi,

I seem to being having my run of problems later, anyway I am creating a lake type scene, I have an infinite plane to which I have applied the Water Lillies Liquid.

If I render with a standard atmosphere or even spectral no problems, but if I render with Radiosity all the lillies that float on the surface on bright purple! 

As you can imagine it kinda makes the image look a touch naff, has anyone come across this before or know of a workaround? I really want to keep the lillies in the picture.

Jon

This could be several problems.
Check your 'Highlight Color' for the lillies and also check Every color in your 'Atmosphere editor'.
If they all look OK, then make subtle changes one by one until you find the culprit.
I used Radiosity on this image : LINK : and the lillies came out fine, but I do remember adjusting light colors to get what I wanted in the Atmosphere Editor.

Hey Thelby,

Thanks for the info. There is no highlight colour for the lillies, well its white anyway :) The lillies are procedural too, and I have checked the sky and there is nothing even remotely purple in it. Strangely the mini preview window shows the picture ok.

Even the pre-pass shows them up as bright purple.

I will try a different atmosphere and see what happens.

Cheers
Jon

first... try same atmos, but turn off radiosity - turn it down to say, AO or GI and see if the purple shows back up.  If it does, its the atmos, if not, then it could be the radiosity doing something strange.

It was the atmosphere I was using, have changed atmosphere and all was fine. Sorry I didn't post my results early, have been out today :)

Cheers
Jon

no prob =D  atmospheres can do strange effects, even without any obvious reason...

grins

Hi,

On further examination it turned out to be nothing to do with the atmospheres. It was the render settings.

For some reason on Superior, it changed the lillies purple, when I changed the atmosphere a second time I reverted to final mode for a test run which is how it renderered normally.

When I upped the render to Superior with that same atmosphere, the problems occured. Anyway changed to my custom render settings and no problems, same for final and ultra, all work ok, its just superior that has problems, I have no idea why.

Jon

I never use Preset Render settings, there are OK until you know your way around Vue, but after that they are of no use to me. Glad you found the problem!!!

I second Thelby completely. The preset render settings are pure rubbish, I stopped using any of those a very long time ago. They're all unbalanced (some have too high advanced effects settings and at the same time too low AA settings, for example).
The effect you described seemed like radiosity light leaks. If that is so, then the culprit was the advanced effects settings that were too low.

Thanks Thelby and Rutra,

I really can't nail it down to any one thing, the purpleness appeared only on superior, but not on final where the advanced effects settings was lower or on ultra, where it was higher. I have tried multiple settings since I posted here and nothing apart from superior causes the problem.

For final rendering I use my own settings, I use final and superior when I am making a scene, usually for quick render purposes, my current scenes renders in 2 mins on final and 5 on superior. With my own settings and a higher render size it looks like it is going to be 2 - 3 hours :) 

Jon

It does take some time and experiments to nail down completely all the nuances of the user render settings. But once you do, it's much better. You will be able to have lower render time with higher quality.

One very important thing that is often neglected is the quality boost in the light tab of the atmosphere settings. I must have said this already in 20 different posts but it's never too much. :-) This slider can be set at negative values and this generally has a big impact in render times. For example, I usually use -4 or -3 in this slider. The higher the light balance is (i.e, more towards the sun), the lower you can set the quality slider. The symptom that the slider is too low is when you start to see blotches in the shadow areas.

Regarding the light leaks, if setting the advanced effects setting at high levels alone doesn't solve it, you'd have to change the number of photons or the radius of gathering photons (click on edit next to this slider).

I suggest that you don't use infinite planes for water planes. I only use those if water is visible to the horizon in my images (and even in these cases, not always). I normally use cubes for calm water (and terrains for rough water). I find that with infinite planes it's harder to get a good balance between transparency and reflection. Also, because infinite planes are planes (i.e, very thin) they are more prone to light leaks. It's much easier to not have light leaks with solids, like cubes or similar. Very thin objects (like planes) are very prone to light leaks.

If even with solid objects you see light leaks, make sure that the photon gathering radius is not bigger than the thickness of your object.

Another thing that creates huge light leaks is self luminosity in objects. Make sure that no material in those flowers have self luminosity, not even a little bit.

Ah some good advice there Rutra thanks :) 

I have had mixed results with planes for water and cubes, overall cubes do work better, I can't remember now why I used an infinite plane for the water this time but for the moment at least the scene looks ok.

As for those damn plants, I am still trying to work it out. I rechecked my render settings and it seems I didn't use ultra, just final and superior. It could be texture anti-aliasing that's causing the problem, as that isn't used in final and I don't use it in my own settings but I noticed its on in Superior. Either way its odd, but something I don't come across often thankfully :) 

Jon