View Full Version : Transparency Noise

06-08-2010, 11:34 AM
Hi There!!
I taking lots of problems with LW 9.x Series because the noised transparency in the cameras!!
I posting the scene, object and textures to tests!!
This scene was rendered in the LW 8.5 and the noise artifacts have no exist!!
The hair texture on LW 8.5 is ever perfect and not fail!!

Tips about tests:
I turn on and turn off the Mipmap effect, but it have no results on render!!
Please, I need some help here!! ^^


06-09-2010, 01:16 PM
Somebody got the scene and made any test!?

06-09-2010, 04:35 PM
I'm checking it out... it renders SO slow it's hard to troubleshoot, I'll get back to you

06-09-2010, 05:43 PM
Ok basically two things wrong with your hair piece.

1. why on earth are you using 3 2000x2000 images on a clump of hair????
(Danner shakes his cane menacingly. "those kids today I tell you they never had to wrestle with a computer with 12mb of ram". ) I reduced the textures to 256x256 and it actually looks a tini bit less noisy and renders a whole lot faster.

2. The biggest problem was really your specular map. Keep in mind that when you apply a transparency map to an object, the specularity is not canceled with it. so you will get shinny areas where your object is transparent (like a shinny plastic bag) So you had areas with no hair, but with specularity showing, very noticeable where your first arrow is pointing. To correct that. use the same map you are using for transparency on the specularity channel but inverted.

06-10-2010, 07:46 AM
Danner - Ok!! So, because the LW 8.5 have no noise even using oversized textures!?
I will need change all my textures in my models to achieve a good rendering in the 9.x series!?
I really believe that 8.5 series have more accurate render solution!! (_)
I don't wanna believe that 9.x series need ever low res textures to work nicely!! (^.^)

I doing several tests too, but the settings of AA is getting really lots of time to render in a good quality!!
In the sometimes it get almost double time of 8.5 series!! (>.<)

06-10-2010, 08:04 AM
Oh, and I would lover AS Threshold a little too, it's a bit high, then you could lower AA passes.

06-10-2010, 08:14 AM
Matt - But with Threshold The general appearance of rendering look a few blurred!! _
I cannot have a sharp and antialiased image anymore!?

06-10-2010, 12:20 PM
I haven't used lw8 in ages so I can't realy compare, but the rendertimes in 9.6 should be better specially using radiosity. 6 AA passes and adaptive sampling of .05 is usually good enough unless you have very contrasting textures or tini patterns. If you turn up your AA things like diagonal lines will look better, if you lower the adaptive sampling things like grids and tini textures will look better. Every scene is different and as such I use different AA settings for every scene I make. I try to stay away from oversampling or use very little because some things might look too soft.

When working with radiosity you have to also try to stay away from double sided polygons. They take much longer to render and can look odd (wich side is receiving the radiosity?) Yesterday I forgot to mention that your bump map was also way too strong.

To find the balance in antialias settings I turn off radiosity, reflection, raytrace transparency, refraction.. sometimes even shadows. That way I can make lots of little tests.

06-10-2010, 05:10 PM
from my test using classic camera in 96 with Classic, Low AA quality boosts rendertimes.
so as far as i can tell your rendertimes in 8 must have been darn high (?)

can you test it /check?

06-10-2010, 05:51 PM
LW96 behaves differently, probably due the AA fast Motion Blur technique.

try to Gaussian blur the B/W stripes.

06-11-2010, 06:41 PM
Ok I had a mess on and managed to get a pretty reasonable smoothness to it.

I removed the adaptive sampling (having it on at too high of a setting seems to slow down the render, as opposed to having it off, with a decent AA value, though this well may be scene dependant) and used better reconstruction sampling (box is a nice favourite of mine at the moment)

Scaled down the textures, and cleaned them a little (if you have non JPG versions please don't use JPG's for textures, ever again!) PNG's are about best.

Most importantly, I used your transparency map, and created a clip map, which handily I could apply using your UV coords, which loses no data from your textures (I Used the outer most pixel level). This really makes the big difference, and solved most of the issues with your transparency material.

Of course settings for just the hair may be throwing off other things in the scene, so it may be about getting the right balance of settings for all the other materials and lighting in the scene.

06-12-2010, 03:27 AM
in the example Tobian posted, if you turn off the transparency you also boost the rendertime to 1/4th.

it will look a bit cheaper, still...
rendertime 60sec

06-12-2010, 03:36 AM
no GI, no transparency
(clipmap, AA17)

rendertime 22sec

06-12-2010, 03:53 AM
this is one of the trickiest scenes i ever tested,
rendertimes are rocket high in order to get a decent result.

and it is basically all due high AA must be used.

06-12-2010, 05:35 AM
Well I think you'd have to modify the clip map to get it to look roughly the same cut as before, I just made sure when I made the clipping mask I wasn't throwing away any of his actual hair :) and yeah it is really tricky, I had to really mess on to get it to go faster, and with adaptive sampling almost the entire thing has to be resampled, so you may as well just ramp up the AA. Adaptive sampling performs poorly in this case, as fine lines really must have AA sampling to maintain their integrity, AS doesn't really work.

I forgot to mention also I lowered the area light quality to 3, to help save some time... Visually it doesn't look different, but then that doesn't mean anything, as it may affect other bits of the scene with soft shadow noise...

06-12-2010, 06:38 AM
having tested, plain polys are actually the way to go

this example looks bad, but the AA is good and at 55sec rendertime.
remodeling this hair has to be done. (obviously)

so, lesson learned, for thin hair, do not use clipmaps / transparency maps.

06-12-2010, 08:45 AM
Hi guys!!
Thanks for the great feedbacks!!
I testing the Classic Camera on the LW9.x!!
Take a look in my finished works gallery!!
The hair looks very better!! Not so good like 8.5 results but is good!! ^^

So, look that a lot of problem is the new cameras AA, maybe!!
I will post the LW8.5 result!!

And if you wanna do a really hardcore test, just put this hair to reflect in a mirror!!
The reflection image is totally noised in the 9.x!!