Help Please

[architect-sma]

I have been recieving help from a number of users in the last few days about a MR problem. They have been a help, however now I am having another problem with final gather. It was first suggested to me to increase my number of photons and manipulate the radius so as to get good lighting. By just manipulating these setttings I should be able to get a rendering which is almost complete, then I add a "little" Final Gather to fix any other dark, blotchy areas, etc. Please refer to the two thumbnails I have attached. The first image is w/o FG and is of fairly good quality, I should only have to add a little FG to make it final. However, when I add the FG (second image) the image gets those weird squares of different light qualities on the walls and floors etc. I know it's not the bucket size because the bucket is at its highest setting of 512. Anyone have any other suggestions for the final gather? Any help is appreciated as I am running into a deadline here at work on Monday.

[William Alexander]

Are you rendering the view that the final gather was calculated for?

 

FG is view and resolution dependant, and typically the boxy or large pixel effect happens in different views and resolutions from the view used to figured the FG Solution. From my experience.....

 

WDA

[architect-sma]

Thank you for your response, yes that was the only view I had calculated it for, however, I'm not sure if I should be checking some of the boxes I have been checking. Should I check any of the "Fast Lookups", "Rebuild", etc. boxes that are under Indirect Illumination? I'm just not sure, I was a lightscape user until recently, my firm wanted to upgrade to Viz, now I'm having to learn this new renderer. Any help on the settings is appreciated. Samples are at 1,000. Thanks for the help I really appreciate it!

[William Alexander]

Checking Fastlookup is knind of an aximoron, it's a better method but slower.

 

Do you get this problem when rebuild is checked and unchecked (with the use file option- FG map saved to disk)?

 

Nisus had a similar problem in the Max forum- you might want to do a search.

 

The photon map looks good, have you tried decreasing the FG max radius? If the room (overall scene) is 20'x20' the default max radius will be like 5'. The circumferance of the FG sample is 1/4 of the room, not much detail in that, possible that it might be the problem. A max sampling radius of 1' or less gives good results for imperical measurements of residential living spaces. In this room you may need 1500-3000 samples, you can cheat the clac times down a bit by specifing a min radius of 1/10 of the max radius (rule of thumb), 2.5"-3" might work also- the sampling is not as precise and cpu intensive.

 

Give it a whirl if you can!

 

I'm looking for a link I ran across on the XSI site that does a very good job explaining the MR parameters- wish I'd found that before coming to the same knowledge by trial and error;). If I find it I'll post it.

 

Cheers

WDA

[Fran]

I know I sound like a broken record, but FG has an issue with cameras that have manual clipping enabled.

[joske]

see the attachment for settings FG

if that does not get rid of the box effect try a different camera or swith to perspectieve view ... if that doesn't help reset max and merge your objects in your new scene (start with all render settings in default)... if that does not help email me the scene and i'll have a look at it, ... should not be difficult to spot the prob .

[architect-sma]

Thank you very much for the help, I will try that and let you know how it goes. If no inprovement, I will e-mail the scene to you. I really appreiciate your time. One last thing, I'm actually using Viz 2005 not Max. (Basically the same thing, especially using the MR from what I understand). Thanks again, I really appreciate it.