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HEKTOR
08-26-2007, 05:41 PM
Hello!

I have stupid problem. When i render scene with Gi everthing is ok but if i turn on FG i have Boxes on render :sad: , i try put FG on 10 000, and i have stil that same numer of boxes. Ehhh i don't know what to do. Please helpppppp!

Sorry for my English!

http://www.tibik.nazwa.pl/Grafika/Forum/cgtalk.jpg

Hasnz
08-26-2007, 06:03 PM
very strange !
have you tried only rendering with FG . can u show ure render global settings .

HellstormDe
08-26-2007, 07:42 PM
Did you check "Precompute Photon Lookup" in the Render Globals?

I would also like to know if the "box" size is the same as the mental ray render tile size.

HEKTOR
08-26-2007, 09:11 PM
Hello!

First off all, really Thanks for interest my problem.

I turn on the "Precompute Photon Lookup" and turn off, that same problem.

"I would also like to know if the "box" size is the same as the mental ray render tile size."

No... if i render in biger res, i have much many box it's smaller. But it is still.

This my render globals
http://www.tibik.nazwa.pl/Grafika/Forum/Render_globals.jpg




Sorry for my English !!!

Thanks for any help!
Greetings!

HellstormDe
08-27-2007, 05:44 AM
Only some ideas:
set FG Max Radius to 10% of your scene size and set Min Radius to 1% of your scene size.
Set the trace depth a bit lower (eg. 3 refract. and 3 reflect, 6 max) and also try a filter size of 1 if it still doesn't help.
Decrease final gather rays to 1000 and check Secondary Diffuse Bounces.

HEKTOR
08-27-2007, 09:54 AM
Ehhh... I put everything as you write :cry: it don't work :sad: I don't know what to do, maybe problem is with setings a memory or somethink like that :sad:

But... thanks for help!

Lyrid
08-27-2007, 01:11 PM
according to global rendering setting image you posted:
set global illum accuracy to 1200
turn off precompute photon lookup
final gather rays is 100
final gather's trace depth 2
trace reflection 1
trace refraction 1
turn off preview final gather tiles
and rendering...

if it doesn't work, maybe you can post the scene file here. we test it.

HEKTOR
08-27-2007, 02:45 PM
Lyrid Thanks i think it works. I setup:

global illum accuracy to 1200
turn off precompute photon lookup
final gather rays is 1000
final gather's trace depth 3
trace reflection 2
trace refraction 2
turn off preview final gather tiles

And i have something like this:
http://www.tibik.nazwa.pl/Grafika/Forum/k2.jpg

I thik is better, but i still see boxes, but small. Turn up FG ? to 3000 it very long render.

slipknot66
08-27-2007, 03:28 PM
Is that background image applied during render? as a image plane?
If yes, try to render with the old values you were using for FG and GI, but without the image plane for the background.See if it works.

slipknot66
08-27-2007, 03:30 PM
Are you using Maya 8.5?
Because in Maya 7 the Maya area lights were not supported by mental ray.

tfritzsche
08-27-2007, 06:21 PM
hi HEKTOR
I recognize the scene from the lighting challenges here on CGTalk.
It looks as if you are using Maya v7, yes?
To tune the scene using GI and FG, start off with getting a good GI solution with no FG, start with GI accuracy at 300 and a radius of 1, this will produce a very spotty result, but what you are looking for is good photon coverage from your lights(oh yes, you did turn on emit photons on your lights?no photons = no GI)if there are not many splotches increase the photons on your lights by x3, once you get good coverage(30-50%) increase your radii, in render globals, to 9 and accuracy to 900 and filter to 1, this should be close to a smooth solution (increase radii by ~3's and accuracy by ~200's). Then for your FG start at an accuracy of 100, and set your min and max radii to 25, and check view radii in pixel size. Slowly increase your accuracy by 100's if necessary.
In Maya 8.5 I would not use GI at all but multi-bounce FG.

This is a very simplified explanation, but will hopefully get you on your way

thomas

myself44
08-27-2007, 07:26 PM
In Maya 8.5 I would not use GI at all but multi-bounce FG.

I've heard many ppl say that.. but why GI is not needed anymore in Maya 8.5 ? (I just updated)
How can I enable and render in multibounce FG ? Does this has anything to do with Physical Sun & Sky ? Maybe this is the solution to light interior along with PhyS&S... because PhyS&S gives very, very, very dark interior render (even when set at a high multiplier)

tfritzsche
08-27-2007, 07:44 PM
I would not say its not needed, just the quality of FG multi-bounce is much better than in the past, and GI can take longer to set up. Some scenes still require GI for optimal renders. When working with PS&S its important to gamma correct your textures and either render to 32-bit hdr or tone-map the 8-bit and 16-bit images - there are some long threads about these issues.
http://forums.cgsociety.org/showthread.php?f=87&t=452901
http://forums.cgsociety.org/showthread.php?f=87&t=190232
and some nice summeries:
http://forums.cgsociety.org/showthread.php?f=87&t=385107


thomas

myself44
08-27-2007, 07:59 PM
I would not say its not needed, just the quality of FG multi-bounce is much better than in the past, and GI can take longer to set up. Some scenes still require GI for optimal renders. When working with PS&S its important to gamma correct your textures and either render to 32-bit hdr or tone-map the 8-bit and 16-bit images - there are some long threads about these issues.
http://forums.cgsociety.org/showthread.php?f=87&t=452901
http://forums.cgsociety.org/showthread.php?f=87&t=190232
and some nice summeries:
http://forums.cgsociety.org/showthread.php?f=87&t=385107


thomas

oh well, thx for these. Pretty went through the first two but never knew that third link. Thx!!

HEKTOR
08-27-2007, 08:23 PM
Hello!

First of all i use MAYA 8, when i turn on or turn off the Plane with image behid the window i have that same efects:

http://www.tibik.nazwa.pl/Grafika/Forum/k3.jpg

http://www.tibik.nazwa.pl/Grafika/Forum/S_K3.jpg

And i turn up FG and have this:

http://www.tibik.nazwa.pl/Grafika/Forum/k4.jpg


http://www.tibik.nazwa.pl/Grafika/Forum/S_K4.jpg


Now i be in sock, ehhh it's horible i wan't learn rendering buuuuut i cant :banghead:

Ehhh i put scene maybe i set some thing wrong :(

http://www.tibik.nazwa.pl/Grafika/Forum/9.mb

camera to rendering have name: kamerka
camera like perspective have name: pres

tfritzsche yes i do as you write, on first i put lights, then i turn on GI and setup everytnig ok, when result of lighting is OK i turn on FG and i have sock and despair :cry:

Kako
08-27-2007, 10:15 PM
EDIT: Oops! My bad! I hadn't read the last post completely. Sorry!

Hi Hektor.
Would you share your scene as it is so that we can make some tests?

HEKTOR
08-27-2007, 10:23 PM
Yes, i put scene, make some test. The scene is form www.3drender.com (http://www.3drender.com) is modeled by Jeremy Birn.

Kako
08-27-2007, 11:00 PM
Hektor,
I opened the scene and made a test. I didn't get the tiles you're getting, but the result was still a little odd.
The problem is that the camera is looking through the wall and the door, which have the "double sided" attribute turned off. Somehow, the render doesn't come out right.
So you'll probably fix it translating the camera a little bit to the front, until the door and the walls aren't blocking it anymore.

Hope it solves your problem.
Kako.

slipknot66
08-27-2007, 11:47 PM
Kako is right, i did a test render here, and the camera was the problem, also some objects were not visible to reflection and refraction, that can cause those squares problems.

myself44
08-28-2007, 12:01 AM
Omg... 1000 FG rays... I never went beyond 400 in my projects .... I took my computer actually 5 long minutes to see the first little square of the render appear on the blue window...
Sry I couldn't help, my machine is really too slow
BUt one thing.. I noticed that I can't move the render camera... how do you lock it like that ? Never knew you could ..

Kako
08-28-2007, 12:33 AM
myself44,
Some attributes of the camera are locked. Select the camera and look at the channel box. Select all the attributes marked in grey and right click > unlock selected.
Now you can move the camera.
Kako.

myself44
08-28-2007, 01:29 AM
First of all, don't know if yo checked, but there's a thread concerning this VERY scene rendering here : http://forums.cgsociety.org/showthread.php?f=185&t=315513&page=1&pp=15
Maybe there will be informations, I'll read that myself tomorrow :)

Hektor, learning rendering with MR is very frustrating at beginnig... I struggled a few months with MR before able to do decent renderings... but what I do is make a simple light setup once the empty room is modeled, so I can have a approximate idea of the light quality, then I move on modeling the rest of the obejcts, rendering time to time so I can see if there anything cause any problems... worked well for me. But I see this is a downloaded scene, and I always had touble and problems with downloaded scene...
So when you'll create your own scene, you'll have more control and knowledge imo

This is real wierd. I bumped down all settings GI and FG (about 500 accuracy and 100 rays), but when I render, I start to see the first glimpse of the image and booom... everything freezes.
No more render... It just keeps saying Computing FG rays forever...
I tried other scenes and everything's fine, so there's something with this file

And can someone tell me how to activate the "FG multibounce" method without GI , so I can try out ?

HEKTOR
08-28-2007, 09:32 AM
Ohhh... It's work :bounce: only move camera, what I'm stupid man :D


Thanks guy's for help!!!

tfritzsche
08-28-2007, 02:34 PM
And can someone tell me how to activate the "FG multibounce" method without GI , so I can try out ?

myself44,
First, FG multibounce can only be activated when GI is off.
Depending on your Maya version, settings may be different, I don't recall v7 having multibounce, I think it was introduced in v8, I upgraded from v7 to v8.5. In 8.5 render setting FG tab tick the secondary diffuse bounce check box, then in miDefaultOptions node I set FG diffuse bounce, reflections, refractions and max depth ( default values are a good start) - all values will be capped by the max trace depth.

thomas

tfritzsche
08-28-2007, 03:01 PM
HEKTOR
took a look at your scene, and I see we all have discovered the camera in the wall issue.
On your lights I see you have the decay set to off to simulate sunlight, for realistic results you probably want to mimic this in your photon emmision, right now your photons have a quadradic decay, exponent of 2, a setting between 0-1 would match your direct illumination, you will need to re-balance your direct illum to your indirect illum photon intensity. Also you need 5-15 times the amount of photons a setting around 150000, imo. I think a GI radius of 12+ is in order. FG then can be in the 100-300 accuracy range with the smoother GI solution.


good luck
thomas

HEKTOR
08-28-2007, 03:21 PM
tfritzsche - exponent is for decay? Oh shi* i don't know, Thank's MAN, i still have very much to learn :)

slipknot66
08-28-2007, 03:23 PM
myself44,
First, FG multibounce can only be activated when GI is off.


Actually you dont need to turn GI off to use secondary diffuse bounces, i use 2 bounces with GI and it works without any problem, you can clearly see a difference when combining 2 FG bounces with GI.

tfritzsche
08-28-2007, 07:11 PM
Actually you dont need to turn GI off to use secondary diffuse bounces, i use 2 bounces with GI and it works without any problem, you can clearly see a difference when combining 2 FG bounces with GI.

Yes, you can have secondary bounces with GI, this is controlled by the photon tracing attributes of GI in the Render settings. FG will give GI the last "bounce" to the camera, but secondary FG bounces have no effect. Correct me if I am wrong I'd love to have that extra amount of control in my scenes, but all my tests (Maya v8.5 sp1) have shown no contribution of secondary FG bounces when GI is active, over the FG contribution to GI.


thomas

slipknot66
08-28-2007, 09:58 PM
Well i did some tests when secondary diffuse bounces were introduced in Maya 6.5, and at that time i noticed that FG secondary diffuse bounces still works when using GI, and you can see some differences when using both methods together.Here is the link to the old thread i did.

http://forums.cgsociety.org/showthread.php?f=87&t=214487&page=2&pp=15&highlight=slipknot66

I still use GI+FG+FGsecondary diffuse bounces with Maya 8.5, but to notice the difference when combining the methods, you need to use low intensities for the photon map, then its a matter of adjust everything to get the light you want.And even with the new mia_material that have ambant occlusion integrated, i prefer to use the old method of area lights in front of each window, and those lights are the ones i use to emmit photons, combined with FG+FG secondary diffuse bounces.I could get some nice results using this method, also i didnt noticed any render time increase when combining FG secondary diffuse bounces with GI.

myself44
08-28-2007, 11:41 PM
Well i did some tests when secondary diffuse bounces were introduced in Maya 6.5, and at that time i noticed that FG secondary diffuse bounces still works when using GI, and you can see some differences when using both methods together.Here is the link to the old thread i did.

http://forums.cgsociety.org/showthread.php?f=87&t=214487&page=2&pp=15&highlight=slipknot66



OMG, slipknot, that scene is awesome !! Im impressed by the simplicity :
"2 point lights converted into mr area lights.
min/max radius left at zero"

Is that all ? Only FG ?
What do you suggest me to do since now in 8.5, point lights don't have "MR arealight" option anymore... is spot lights more appropriate ?

slipknot66
08-29-2007, 01:53 AM
Thank you myself44
I used GI+FG(with 2 secondary diffuse bounces)
Now you can use the Maya area lights.

myself44
08-29-2007, 02:01 AM
Now you can use the Maya area lights.

Ok, but I mean, is there a need to check "MR AreaLight" inside the Maya AreaLight attributes ? It would be like converting an Area light to an Area light.. kind of weird

slipknot66
08-29-2007, 02:03 AM
No, theres no need to check anything, now the native Maya area lights are supported by mental ray.

slipknot66
08-29-2007, 02:11 AM
No, theres no need to check anything, now the native Maya area lights are supported by mental ray.

Sorry, actually you need to go to the mental ray tab, and check use light shape :)

tfritzsche
08-29-2007, 03:13 PM
Well i did some tests when secondary diffuse bounces were introduced in Maya 6.5, and at that time i noticed that FG secondary diffuse bounces still works when using GI, and you can see some differences when using both methods together.Here is the link to the old thread i did.

http://forums.cgsociety.org/showthread.php?f=87&t=214487&page=2&pp=15&highlight=slipknot66

I still use GI+FG+FGsecondary diffuse bounces with Maya 8.5, but to notice the difference when combining the methods, you need to use low intensities for the photon map, then its a matter of adjust everything to get the light you want.And even with the new mia_material that have ambant occlusion integrated, i prefer to use the old method of area lights in front of each window, and those lights are the ones i use to emmit photons, combined with FG+FG secondary diffuse bounces.I could get some nice results using this method, also i didnt noticed any render time increase when combining FG secondary diffuse bounces with GI.

I looked at the thread, you show an image that you rendered with GI+FGmultibounce, then images with no GI but FG and FG multibounce. So I downloaded your scene file, rendered it in Maya 8.5 as received, GI+FG multibounce, then I rendered without the multibounce, GI+FG only. No difference in the renders, here are the jpegs

myself44
08-29-2007, 06:28 PM
Ok, slipknot ?
I took a look at your kicthen scene file (http://forums.cgsociety.org/showthread.php?f=87&t=214487&page=2&pp=15&highlight=slipknot66)

And, I think these last few days, by looking and opening scene files, I've learn alot more than just reading thread and websites.
I saw in that scene, there was some IBL nodes... I was like wth is that. Googled it and now I think Im going to read a bit about Image Based Lighting. I still don't what it consists of, what are the advantages, the uses.

But Im trying to get the puzzle together (my knowledge about rendering and MR was nearly 0)
now I learned about the principes and methods of GI+FG, then multibounces, now IBL pops out, is this another method of lighting ?

anyway , I'll take a look at some resources on the web and if I have other unanswered questions, I shall bump up this thread :P\

btw, why should we apply mia_materials everywhere ? I see that your phongs do the job very very well in the renders above. mia_materials do take longer to render than Maya material, no ?

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