Mental Ray / Final Gather / Buckets problem

Ras · October 27th, 2004

Hi Everyone

I am teaching a Viz Class at my former school and have run into this problem that I´m unable to solve.

Whenever I use final Gather on an interior view I tend to get problems with the buckets showing up in the final rendering. I´ve definately tried upping the FG samples but it doesn´t really help.

My colleague Allan (AKA "Architect" in here) posted in the Max forum yesterday but we are working on Viz at the school so I thought I´d post here and show an updated piccy.

we were trying to not use too many lights in the scenes for educational reasons but now we have conformed to the need of using area lights instead of just a skyligt.

I´ve uploaded a revised scene and rendering to show the problem. I´d really appreciate your advice on this.
This is a project of one of the students. It has been particularly hard to get around because of the very few windows in the room.

Thank you very much

Fran · October 27th, 2004

Hi Ras,

This could be an issue with enabling manual clipping on the Camera. Is that the case here? I think I've had success creating an FG map in a view without clipping and reusing it in a view with camera clipping.

kicks · October 27th, 2004

<ditto. Manual camera clip is the cause.

auvn · October 27th, 2004

Your hardware migh be reponsible for the problem. I just downloaded your attached file and rendered in on my computer. It works just perfectly fine.

( i only reduce the number of photon to 200 and click preview in FG in order to save time).
Definitely the problem is not because Camera Clipping

AUVN
(nice space and very clean model)

how can I upload image on the thread????

kicks · October 27th, 2004

<here's the thread b4. maybe similar problem http://www.cgarchitect.com/vb/showpo...85&postcount=7

<and here is your scene without cam clip. 1 wall & ceiling hidden.
<I also hid glass for faster render.

Quote:

Originally Posted by auvn

( i only reduce the number of photon to 200 and click preview in FG in order to save time).
Definitely the problem is not because Camera Clipping

how can I upload image on the thread????

<just post reply,go advanced then click the manage attachments tab.
<would love to see what you have because i believe you will not get good results with preview in FG.

Ras · October 28th, 2004

Hi guys

Great advice! Wouldn´t have thought of it if you hadn´t pointed it out. Thank you.

What do you do if hiding part of the geometry is out of the question? I know that its easy to detach parts of a mesh to an individual object and hide it from the camera - but is there another way?

Again - thank you very much!

kicks · October 28th, 2004

Quote:

Originally Posted by Fran

.... I think I've had success creating an FG map in a view without clipping and reusing it in a view with camera clipping.

<Ras, you can try this.

Ras · October 28th, 2004

Yeah - but how does FG work - does it calcultate a solution for a room even if it is hidden from the camera? I mean if I don´t hide the wall that I want to near-clip in front of, then I don´t suppose MR calculates the light behind that wall?

kicks · October 28th, 2004

<hey, havent't tried that too. Let's ask Fran.

Fran · October 28th, 2004

You can just try creating a camera without manual clipping and get it inside the room. It doesn't have to look pretty. Then do the final render from your clipped camera re-using the fg map. As far as I know, the fg map is view independent. It's just something you'll have to experiment with.

This is a known issue, but it's hard to say whether it is a bug with mr or the max camera - or whether it can even be resolved.

October 27th, 2004	#2 (permalink)
Fran Moderator Join Date: Jul 2003 Location: Virginia, USA Posts: 1,379 Name: Frances Gainer Davey	Re: Mental Ray / Final Gather / Buckets problem Hi Ras, This could be an issue with enabling manual clipping on the Camera. Is that the case here? I think I've had success creating an FG map in a view without clipping and reusing it in a view with camera clipping. __________________ - Fran If you must reinvent the wheel, remember that it works best if it is, like, roundish.

October 27th, 2004	#3 (permalink)
kicks Senior Member Join Date: Jun 2004 Location: dubai Posts: 425 Name: patrick deno desamparado	Re: Mental Ray / Final Gather / Buckets problem <ditto. Manual camera clip is the cause. __________________ kicks IF YOU DIM YOUR LIGHT SO THAT OTHERS MAY SHINE, THE WHOLE WORLD GETS DARKER.

October 27th, 2004	#4 (permalink)
auvn Junior Member Join Date: Aug 2004 Location: Cambridge Posts: 23 Name: duong bui	Re: Mental Ray / Final Gather / Buckets problem Your hardware migh be reponsible for the problem. I just downloaded your attached file and rendered in on my computer. It works just perfectly fine. ( i only reduce the number of photon to 200 and click preview in FG in order to save time). Definitely the problem is not because Camera Clipping AUVN (nice space and very clean model) how can I upload image on the thread???? Last edited by auvn; October 27th, 2004 at 10:18 PM.

October 28th, 2004	#6 (permalink)
Ras Senior Member Join Date: Oct 2002 Location: Denmark Posts: 196 Name: Rasmus Groth	Re: Mental Ray / Final Gather / Buckets problem Hi guys Great advice! Wouldn´t have thought of it if you hadn´t pointed it out. Thank you. What do you do if hiding part of the geometry is out of the question? I know that its easy to detach parts of a mesh to an individual object and hide it from the camera - but is there another way? Again - thank you very much! __________________ Regards Ras

October 28th, 2004	#8 (permalink)
Ras Senior Member Join Date: Oct 2002 Location: Denmark Posts: 196 Name: Rasmus Groth	Re: Mental Ray / Final Gather / Buckets problem Yeah - but how does FG work - does it calcultate a solution for a room even if it is hidden from the camera? I mean if I don´t hide the wall that I want to near-clip in front of, then I don´t suppose MR calculates the light behind that wall? __________________ Regards Ras

October 28th, 2004	#9 (permalink)
kicks Senior Member Join Date: Jun 2004 Location: dubai Posts: 425 Name: patrick deno desamparado	Re: Mental Ray / Final Gather / Buckets problem <hey, havent't tried that too. Let's ask Fran. __________________ kicks IF YOU DIM YOUR LIGHT SO THAT OTHERS MAY SHINE, THE WHOLE WORLD GETS DARKER.

October 28th, 2004	#10 (permalink)
Fran Moderator Join Date: Jul 2003 Location: Virginia, USA Posts: 1,379 Name: Frances Gainer Davey	Re: Mental Ray / Final Gather / Buckets problem You can just try creating a camera without manual clipping and get it inside the room. It doesn't have to look pretty. Then do the final render from your clipped camera re-using the fg map. As far as I know, the fg map is view independent. It's just something you'll have to experiment with. This is a known issue, but it's hard to say whether it is a bug with mr or the max camera - or whether it can even be resolved. __________________ - Fran If you must reinvent the wheel, remember that it works best if it is, like, roundish.

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