Radiosity Interor Problems

[Lude]

I’ve got weird lighting problems; it looks like the light from the dome out side is seeping through my walls. I’ve made totally sure that there are no gaps. What’s going on?

[ruud]

show me a wireframe, could be a problem in the model.. otherwise... what pixelfilters are in the pic.?

[iluvatar]

hmm did you create the room as cube and substracted another cube out of it, or did you create the walls and added a floor and ceiling seperatly, as flat 2D poly's? if the ceiling and floor are seperate poly's are you sure the points of the ceiling are merged with the points of the walls? only thing i can think of this moment...

[Lude]

oh by the way im trying to use interpolated to be faster.

[ingo]

Well normally Lightwave's Gi doesn't care about geometry, compared to crappy Lightscape. Could it be that your globe is glowing a bit to high, like 1000 % luminosity for example ?

[cathuria]

Yes, I can see you're using interpolated; it's prone to blotchiness and uneven shadowing -- motion blur can actually help smooth that out.

Interpolated will also sometimes light up shadow areas like that, but I've never seen the effect quite that bright. If the problem is with the radiosity, cranking up the number of rays and/or switching to the much slower but superior Monte Carlo should solve it.

The other thing that occurs to me is... does this room have some "outside" polygons to stop the flow of light (i.e., a roof & outside walls)? If not, try making the ceiling & walls double-sided, that should stop extra light from filtering in.

[Lude]

Ok guy’s thanks for your suggestions.

I've changed my surfaces to be double sided and that seams to have sorted my problem.

This is my last render using interpolated, as u can see it’s still blotchy.

So I tired using Monte Carlo but 2 days of rendering later my computer crashed – AHHHH. (2 bounces 1024 x 768 with enhanced low aliasing on a +2800 with 1Gb)

So I’m going to go back to messing about with interpolated to try and get a good setting.

Lude.

[Lude]

oh dose any one now how i can reduce the amount of red produced from the light bouncing of the floor?

[Lude]

new render.

I have removed my sky dome. Gone with a 1 bounce solution for speed and turned of reflections etc.

I was just trying to get the lighting right first.

10% Ambient and 350% Radiosity.

About 8.5 Hours to render what you see here.

Lude

[Hervé]

Well, kinda cool , but have you noticed boosting rad is not ideal solution as it makes the feet of couch luminous.... try maybe lowering the diff to well very low...

Many people complained about inside rad, well......

[glassefx]

I seem to almost always get those ole' blotches when performing test runs on the ole F9. What I did to solve my issues was to make the spacing 1mm (std. is 20mm) and make my rays around 3x9 or lower and I get some decent (no blotches).

Sounds like it would ramp up the render times but it actually lowered mine where I get "same day feed-back."

Also... Make sure your walls and ceilings have an outside shell polygon that is 0% diffuse, 0% everything so the light does not come through.....The double sided surface works but your light is bouncing around outside before it even gets to the viewers eyes.

Also, all the big polys (floor, ceiling, walls, etc) should be subdivided into say 25 segments or so. and make sure ALL polys are TRI's.

See what that does for you.

BTW, beautiful render.

as far as the floor casting redness goes.... You could always tweek-down the reflectivity until we get "programmable reflectivity" I bet their has to be some trick to do this while still retaining your original reflectivity setting.

I'll think about that one.

[Lude]

cool glassefx, I’ll try your suggestions out.

Thanks
Lude

[glassefx]

This is from my memory so it is prone to be incorreect, I will check when I go home after work and check to be sure...


I use radiosity with no caustics.

Ray Trace Bounces are 3 or 4.

Interpolated settings are

Tolerance .001

Spacing 1mm

Rays 3x9 and DOWN. SOMETIMES above.

The Tolerance setting is a key I think... You want it as close as possible but on so LW will not have to re-compute the rad solution for each AA pass. Movment or not.

so I may have been setting my tolerance to .0001

I will verify when I get off work.

make sure all your walls,floors,ceiling, are set to ray-trace for the reflectivity. This is a big time eater but it is what you want for a arch/rad render.

Do not start blurring the reflections until you get the shot "tits"
Blurred reflection's algo. must have been written by Worley.

His math is great but does not seem to implement "cheats" to save time.

I think Prem Super Yum Yum is superior in coding dealing with heavy math.

Doesnt it suck when you can't get "same day feedback" from a scene? Im really hurttin' I do my renders on a dual p3 500.

Im not even in the"giga-club" LOL

Speaking of playing with the number of threads (do not know about a single processer machine)will speed up certain renders.

I have 2 but I always usually use 4 threads, it seems to be a snatch faster, could be those silly simons though. ;)

[Lude]

hi again glassefx, thanks for your feed back.

Yeah it's really crap hopping that your test render will be complete by the morning so you can move your project on :(.

What sort of resolution are you rendering at?

Ray Trace Bounces are 3 or 4.
Is this your ray recursion limit or the number of bounces for the radiosity?

As for threads I only have the one processor so i guess there out the window.

I’m still a bit unsure as to the effect of the Tolerance setting I’ve had it set to 0.0 but ill give 0.001 a go.

One more thing, dose the extra ray trace optimization button have much of an effect?

Lude.

[glassefx]

That is my ray recursion limit.

0.0 is no errors and .001 or .0001 are so small you cant hardly see the interpolation "errors"

the extra ray trace optimization..

hum.... I cant seem to remember the if,ands and but on it but I know it can speed up or slow things way down... I will get back to you on that one.

It may only help with animations?

I havent had my 25th cup of coffee yet so...

[glassefx]

I forgot... I usually render tests out at 800x600, extreme things at 640x480, but if I need to see detail, here comes the ole' render limited selection at 1024x768.

Good Luck Lad. Nice chattin' with yah.

[wacom]

The Ray Trace Recursion Limit under the rendering tab makes a huge diffrence. I've found that I can get away with a scene only using 1-4 depending on the "bounces" I want and how many/much refletive surfaces are in the scene.

Some one said something about doing a motion blur and that works well for interperlated stuff- you basicly set it up as you would with the "spinning" light trick with the AA on Medium or Low. If you're going to use AA on a scene you should use this anyway as it can't hurt you most of the time.

Also people talk about uping the rays WAY up...and this is needed most of the time, but you should try (on way lower res tests) using HDR exposure and/or the Full Precission Gamma Image filters. This is NOT the same as using global illumination. I've rendered raytraced scenes quick where you couldn't see a single thing in the final render untill you used one of these filters.

This also brings me to the point that light intensity seems to effect render times. Remeber that in LW if something is "white" or "hot" then more will "bounce" off of it etc. When you crank up the lights it seems to make renders take longer. Lowering your light levels and using an HDR exposure filter or Full Precission Gamma will help with this.

Last you should look into rendering out your highly reflective surfaces seperatly some times as they can lead to a lot of weird bounced lighting (hence your floor turing your place a red/pink color).

Just my 2 cents- I hope this ramble wasn't a waste of telling you things you already know of...

[Lude]

hi wacom

Some one said something about doing a motion blur and that works well for interperlated stuff- you basicly set it up as you would with the "spinning" light trick with the AA on Medium or Low. If you're going to use AA on a scene you should use this anyway as it can't hurt you most of the time.

Im a bit lost by this, i don't have anything set to move that will blur.

Im lighting using 2 area lights should i be spinning these?

Lude.

[glassefx]

No ranting wacom, thats some great info for everyone to use...


Lude, Im thinking that is what he is impling, moving, spinning the lights so the motion blur has "something" to work with.

I'm keeping myself posted on this thread because their are so many combinations possible to save some time...

peace.

[wacom]

With things that create random noise (aka interpilated Radiosity, area lights, etc) it seems this works well. It's not entirely diffrent than using just plain old fasion AA...but it can give you some more flexiblity. As far as I know you don't have to spin the lights in this instance.

Do look into Image filters that play with your gama BEFORE compressing the image down to 32/24 bits in conjunction with lower light settings etc.

I'll try and explain more later...but I'm by no means an expert on this subject...

[Jure]

Have you looked at this tutorial?
http://www.hades-studios.com/hdritutorial

Great tut to cut down render times!

[cathuria]

That's right, it's actually the interpolated radiosity that is "moving" (or rather, I suppose, it's those little splotches that are moving). Motion blur helps to even out the splotches even if you don't have any objects or lights that are moving.