PDA

View Full Version : simple radisity render setup


Nicool
04-30-2003, 08:48 AM
Hye,
I've tried to get a simple radiosity render with mentalRay (maya4), and can't get something correct. First case all is burn, second case it's only the light which bright the scene. I' know the tutorial which exist, and I've already redenr demo scene on my computer well.

So can you give in ~five point (ray, ray sample, ray%%) the typical setup of the light ant of the MR render globals.
It's for my head project http://www.cgtalk.com/showthread.php?s=&threadid=59252

wgreenlee1
04-30-2003, 01:58 PM
Well...
What I did when I first got Maya ws this for a simple GI render...ala radiosity is this...
Just turn out the lights...
In the camera options select the background color and put it about half way....mid grayish
Then in your globals leave globals at default but make sure Final Gathering is turned on,nothing else...no caustics,nothing.
Render.
This pic here was just that...raytracing was at production as was anti-aliasing.
This is just some quick stuff I made...
Just the bare bones of GI with no big jump in settings...
I dont know if this what youre after but this is what Ive been doing a little of....
In the next post I show a little caustics...fast caustics...

wgreenlee1
04-30-2003, 02:00 PM
This time I think I turned the light up just a little....
You see the back drop is doing most of the lighting....

Nicool
05-01-2003, 01:01 PM
Thanks a lot man. I was not knowing about hte camera color :)

bakkaboy
05-02-2003, 12:22 AM
Hey wgreenlee1 -

Thanks for the post on GI & FG. I did what you described, & i get a nice looking pic (albiet your green vertical torus'), however, i can't seem to get any shadows on the plane w/ GI.
When i turn FG, i get shadows, but the image is blown out.

any suggestions?

thanks again

bakkaboy
05-02-2003, 12:26 AM
oh, and i don't have any lights in the scene. I did add a spot & turned it off as per your post, but the scene was black.

thanks

Nicool
05-03-2003, 06:55 PM
don't forget the cam color !!

TiKiMoN
05-03-2003, 10:24 PM
What difference would that make? The camera background color is not affected by lighting. I think he means he has light sources that, when turned all the way off, make the scene completely dark. What I was told was to make a half-sphere to place around your scene, make it some gray shade, and turn up the incandescence. Make sure Final Gathering is turned on in the mentalray globals, and see what that gives you. (You do not "need" light sources for this, but I am not sure what to do when you DO need light sources, because no one will answer my thread. :thumbsdow :shrug: )

wgreenlee1
05-04-2003, 01:34 AM
Heres one lit by a image plane only

wgreenlee1
05-04-2003, 01:35 AM
Here is one with a HDR image mapped onto a sphere

wgreenlee1
05-04-2003, 01:37 AM
Here is another HDR with a little DOF.....

Nicool
05-04-2003, 01:51 AM
Eh TiKiMon, the camera color as an influence on the final gather render. But for your question about the case of an added light... I don't know :)

stunndman
05-04-2003, 02:58 AM
But for your question about the case of an added light... I don't know

What's was the exact question ?

Why he put a light in the scene with 0 intensity ? Most probably to avoid the creation of the default light (which can be disabled in the render globals too).

wgreenlee1
05-04-2003, 04:47 AM
Originally posted by stunndman
What's was the exact question ?

Why he put a light in the scene with 0 intensity ? Most probably to avoid the creation of the default light (which can be disabled in the render globals too).

Oh..crap...
Well to tell the truth.....I keep forgeting about the default light ..... :blush: :insane:

TiKiMoN
05-04-2003, 11:18 AM
Originally posted by Nicool
Eh TiKiMon, the camera color as an influence on the final gather render. But for your question about the case of an added light... I don't know :)

Thanks Nicool... I never would have imagined that the bg color of the camera would in any way effect the scene lighting. I just thought it was there for placing in areas where there was no object in the view.

So do you ever use any actual lights with intensities greater than 0? I know that doing that would cast comparably harder shadows... but right now, I suppose I am still a bit confused on using lights to light a nice GI scene, rather than incandescent objects.

stunndman
05-04-2003, 12:05 PM
as said the light with 0 intensity is just a dummy light - only there to avoid the creation of the default light - if you turn off the option in the render global for the creation of the default light then you wouldn't need it at all

sure you use lights as usual (for simulating direct illumination) - e.g. if you have a sun in your scene or a table lamp in a room, whatever - FG is just used to calculate the contribution of indirect illumination - as does GI - as do Caustics

TiKiMoN
05-05-2003, 09:32 AM
But wouldn't that cast unnaturally hard shadows versus the soft shadows created with indirect illumination?

stunndman
05-05-2003, 11:34 AM
hard shadows are not unnatural - if i take a look at my balcony right now i can see some very hard shadows cast by a very bright sun (the direct illumination)

Albino Eatpod
05-07-2003, 08:02 PM
Just wanted to say thanks for the great, and easy way of producing these types of renders. I've been trying countless ways of doing this, and this is by far the most effective.

CGTalk Moderation
01-15-2006, 01:00 AM
This thread has been automatically closed as it remained inactive for 12 months. If you wish to continue the discussion, please create a new thread in the appropriate forum.