radiosity help

[Tim Saunders]

i am bound and determined to get radiosity figured out (with your help please). i'm using straight viz 2005 scaline renderer. this scene has an ies sun and an ies sky for lights. i am attaching 2 images, the first without advanced lighting, the second with radiosity.

 

1) why do my shadows not cast properly in the radiosity image?

2) the grass, concrete and corrugated metal panels are blotchy and bright.

 

the help files tell me to adjust the reflectance levels of the materials when using radiosity, but when I am using a mixture of 3 or more materials, that gets way too maticulous. are there settings that i'm missing that will halp smooth things out?

 

thnks everyone for your help.

[Tim Saunders]

oh yeah. my settings

i'm using automatic exposure control. pretty much default settings (brightness-50, contrast-50, exposure value-0, physical scale-100). in the radiosity image, i tried leaving refine iterations at 0, and filtering 0, enabled global subdivision at 5'0" mesh size. in the rendering parameters i have regather direct illumination checked with 5 rays per sample, and 10 for the filter radius. that's really all i have played with this time around.

with other projects i would adjust my refine iterations and filtering and the mesh size, but never seam to get things figured out and just end up bagging radiosity all together to make the deadlines. i sure would like to get it this time around though.

[Tommy L]

Radiosity is not my forte but ive heard that its at its best doing internals.

[chuck]

ooohh. radiosity. it looks like your sun isnt on, which would cause the blotchyness on the materials with bumps. max doesnt like bumpmaps that arent hit by direct light. there's probably a way around it though, but i used to just turn the bump down.

 

i'd try this:

 

85%,

 

refine iterations 3

filtering 3

mesh 2'-0"

200 rays per sample

filter radius can stay stock

 

you should be using an advanced material override...it's in the manual. that allows you to adjust reflectance and all that.

 

i haven't used radiosity in a long time, i switched to vray free. much easier to control and set up, and it's much faster....free too. i can get in 5 draft renderings in the time it takes radiosity to do one...

 

chuck

[Tim Saunders]

thanks chuck,

my sun was on. should "use global settings" be checked on my sun't parameters?

no back to vray free. i have downloaded it, but haven't "plugged it in" yet. maybe tonight i'll give it a whirl. now, when you use vray, what lights should i use in an exterior like this (sun, sky). or does vray free have lights of it's own that i will use? let me know because i think tonight is the night for the test. because of coarse i should be able to get it all figured out in 1 night you know. not.

thanks for your help

[Tim Saunders]

okay chuck,

i tried running the same scene using vray free with standard lights (target direct-sun, and skylight) with radiosity inactivated. do i need to use any particular exposure control? i figured there would be some vray exposure control, but no. also, there has got to be something similar to radiosity that is calculated by vray, but where do i get to that? it doesn't appear to be any settings under advanced lighting. alos, about half way through the rendering i got an ugly message that said something like "unhandled exception: rendering region, last marker is at globalillumlight desk::illuminate. send all or part of your scene to chaosgroup. click okay or continue.

and after rendering was done this is what vray messages i had.

[Brian Cassil]

You can use the same exposure control as you do with radiosity. Personally, I prefer to just use standard lights with GI though.

[ecastillor]

i spent about 2 months getting the hold of radiosity and gave it up after one week of using vray....

 

Give it a try!