Radiosity - Shadow Definition on Interior

[MegaPixel]

Ah yes, where to begin...

 

First question - As you can see from the attached image (which is a work in progress) the furniture and detail objects in the scene don't seem to be casting shadows at the same quality as the walls/floors etc. and in some cases, appear to be floating. This is a Regathered rendering illumnated only from an exterior sun source. The global meshing was about 10", FG rays 128 and Filter rad. 30. What can I do to get more shadow defanition around the base of the furniture/chairs etc.?

 

Second question - I'm having trouble getting rid of the "splotchy's" when using Regather to create large images above 800x600. I can't seem to get my filter radius any larger then 30? Recommened settings?

 

Lastly - I'd like to add some lights coming from the sconces and chandaleer. My testing results so far have been very unpredictable. The lights tend to over bleed the scene and influence things they shouldn't no matter how low a candela value I give them. Is it a good idea to add standard lights to the scene - "after" the rad. solution has been calc.d if I'm just looking for a little highlight here and there? How would you go about it?

 

I'm using MAX 7 w/SP 1... 3Ghz Xeon 1Gig Ram... Tests renders are sluggish at best

 

Thanks - Mega

[William Alexander]

You need to decrease the mesh size in the area of the chairs. Regathering can overcome a great deal, but if you are casting a shadow that's 1" wide on a 12" mesh, the effect/occlusion of the shadow is blended over 12". As would the illumination be recieved and cast (raytraced) using large meshing parameters. Imho, it's best to have the appropriate mesh size globally and as needed locally before regathering and such. Also what quality are you running the solution to, the higher the quality the better the apdaptive nature of radiosity, in max, gets. For a scene like this and good quality the longest time possible to calc the solution the better. If it's getting done in like 3 minutes before regathering your quality is low and your mesh sizing could be decreased. That kind of thinking may help also. If you can crank it up to render long and let it go overnight, see what happens.

 

WDA

[MegaPixel]

Thanks WDA,

 

So maybe I'll run a global meshing size at say, 6 - 8" but set the meshing size for my carpet, floor and walls to something like 1"? The image you see in the previous post was done at about 80% and took almost an hour to compute but I could just set it up for 90%+ tonight and let it go overnight to see what happens. How should I handle all of my interior objects which tend to be on the higher poly side? Should I mesh them up too, exclude them, add refine it's, no refine it.s?

 

Regather Illum. still bothers me a little. I can see a tremendous difference in the scene but sometimes too much color blending and splotchyness occurs. If I'm going to run an animation on this scene, I'd like to eliminate the splotchy's as much as possoble because they tend to make the movie look very noisy.

 

Thanks for your help so far - Mega

[MegaPixel]

Quick follow up

 

Just so you know, I ran 90% quality with 1" meshing on the carpet, floor and walls... and I ran out of memory before it even got half way. This was on a new Dual Xeon system with 2 Gig.s DDR2 memory too. I've got to be approaching this the wrong way or something.

[William Alexander]

Quick follow up

 

Just so you know, I ran 90% quality with 1" meshing on the carpet, floor and walls... and I ran out of memory before it even got half way. This was on a new Dual Xeon system with 2 Gig.s DDR2 memory too. I've got to be approaching this the wrong way or something.

 

The floor area around the chairs is the only part that needs that density of meshing. The walls 3-6 inches maybe greater meshing.

 

You may want to try taking the area below & around the stairs by polygon selection and detach it as a new mesh- for lower settings or take those polygons and subdivide them to something around 1" polygons. Then you can use larger meshing globally with close meshing in local critical areas.

 

 

I normally follow this route for determining radiosity & parameters.

 

1. Overall does the scene need large mesh sizes or smaller-far exteriors the default 3.4' or meter maybe too small, interiors I usually start with 12" for meshing.

 

2. Run a rad calc to 85%, how long did it take. Is this going to be a hog at these mesh settings and quality.... then advance it to 90%...95%....

 

3. Keepin in mind the calc times, where is the radiosiy GI working and not working to my satsifaction. Decrease the meshing size to that geometry locally or goto the face/poly level detach or subdivide (tessalate) the mesh.

 

4. Get a decent solution, then consdering refining just a little bit to smooth some of the uneven and splotchy areas.

 

5. Then regather if the above sequence is not good enough. Fran has some optimal settings for regathering and adaptive settings. I belive it's rays per sample=24, turn on adaptive sampling and set the initial to default or 4x4. I don't remember, sorry.

 

It's a balancing act, between many factors. I can lock up and run any sytem out of memory real easy. I'm just trying to help you out a bit, as I have yet to find a set up that works in all cases!

 

The best set up comes from experience, really learning what each of the paremters do and how modeling effects the scene's radiosity.

 

Hope this can be of some help

WDA

[MegaPixel]

I have attached another set of images for you to look at. The difference between my Regathered shot and my Reuse Direct Illumination shot are slim to nill (With the exception that the regather took another half hour to render...). I also took a screen shot of the mesh work on the scene. It seems like alot of my furniture isn't getting meshed right? The China cabinet and sconce lights and really everything arn't really casting shadows like they should be. The shadow quality of the sunlight on the floor is also worse here I think then the original posted shot up above. I hope I'm not going backwards in progress.

 

Thanks again for all your help WDA - mega

 

It would be nice if the Rad. Mesh was smart enough to subdivide itself near object intersections and areas that would need shadow detail Oh wait... Looks like version 7.5 has a new "Adaptive Sub-division" feature for doign exactly that.... Smart Meshing

 

It's also a bummer that I have to run Regather Dir. Illum. to get shadows to appear correctly (Like the window shadow on the dining room floor doesn't appear at al until I do this).

[William Alexander]

Mega,

 

It can be a trip and lead to use of rogain, lol.

 

Just for giggles....

 

Put a spot inside at the window,include only the chairs and rug and set shadows to rayraced, play with the falloffs (manual), shadow color maybe even darken the rug up to compensate and see if that maybe a work around, after the calc.

 

There's still something that's not quite right.... if you can describe the room's dimensions and how you set up the lighting, I'll play with it a bit and see what I come up with.

 

cheers

WDA

[MegaPixel]

WDA, the Dining room is about 13'x19' in dimension. Currently, the only Illumination is coming from the exterior of the room through the windows. I used a Target Direct 2.0 Intensity - Raytraced Shadows - Overshoot Falloff accompanied by a Sky Light 2.0 Intensity - Cast Shadows on (20 rays). Also using Logorithmic Exp. Ctrl. with 75 Brightness, 55 Contrast, 1.5 Midtone and about 2000 Intensity with a 30 Filter size.

 

I've also tried merging the entire scene into a new one just to try to clean up any loose ends that Radiosity sometimes does to a scene. Didn't help much but hey - worth a try. I'm concerend also that every machine in the render farm will have to have the same system specs. as the machine which calc'd the Rad. solution - in terms of memory that is and if I'm running out of memory with 2 Gig.s, I think I'm in trouble.

 

Thanks for continuing to look into this WDA. Your help and interest in the subject has been very rewarding to me and perhaps I can return the favor soon. - Mega

[szi_zsolt]

Hi!

 

As I saw, if you set a filter radius greater than 10 pixels, you will loose details in small shadow covered areas (e.g. behind painting hanging on the wall).

 

I suggest not to go up with Filter radius to 30, but increase the rays per sample dramatically. It will add render time, but it worths...

 

Cheers

[Fran]

Hi David,

 

Try a 12" global mesh with 90% initial quality. Try at least 300 regather samples and a filter raduis of 5 or less. You lose detail with a high filter radius.

 

You can also exclude objects from regathering via object properties.

 

Check the object properties on the furniture that's not meshing. If it's stock, it may have settings you don't want. Control color bleed by using Arch mats or the radiosity override mat.