First radiosity pic & post. Help w/settings please.

[say-g]

im no expert with radiosity so i cant help, but welcome you i can :beer:

[Per-Anders]

to increase your render speeds switch off reflection/transmission blur, it's a killer for render times unfortunately, if you have to have it there what i suggest is compositing, you can render out a verison of the scene using distance falloff on reflections and just luminance channels to create a black and white alpha for blurring he reflection, then of course you need to render a seperate reflection pass as well and composite the blurred reflection back into the original. use lots of small blurs rather than one big blur if you're using gaussian btw (for some reason this gives a much better effect when dealing with alphas etc).

the other thing is as far as the windows are concerned you don't need to have any glass in them as there's nothing being reflected and all it's doing is giving you bad AA (unless you use best settings).

[FusionDG]

mdme_sadie,

Thanks for the help. Yes, I have the blur cranked up in the material reflection channel. I’ll try the composting solution and doing the blur separate.

I’m not sure how to callout the distance falloff on the material reflection channel. I must be looking in the wrong spot.

And I will turn off the windows. I didn’t realize that could have such a strong effect on AA.

And thanks for the welcome say-g

[Per-Anders]

Distance falloff is a free plugin availble from maxons website (plugincafe.com) it's really pretty cool for all sorts of effects.

[FusionDG]

Thanks,

Got it, and some other plug-ins looked like they may be handy so grabbed those too.

[AdamT]

Howdy!

You might have a look at this tutorial if you haven't seen it:
http://www.renderosity.com/viewed.ez?galleryid=233530&Start=1&Artist=mv&ByArtist=Yes&Form.sess_id=13770330&Form.sess_key=1033157342

I think the lighting looks pretty flat in your image. It would be more interesting if there was more direct light from the sun light, I think.

[heretic]

Apply a render tag to the glass w/ seen by GI unchecked..... Also under the chrome material under illumination uncheck for generating radiosity.... Shiny metallic objects, dark black objects and trasparent objects do not need to generate radiosity.... I'm sure your render times will greatly improve........

Also make your min and max samples closer together....

Try:

Min: 24

Max: 50

Also increase your diffuse to 3 for more accurate color bleed....

Hope this helps!

[FusionDG]

Adam,

That is probably the best tutorial to explain how C4D radiosity works that I have seen. I saw that a while ago but lost the bookmark. This time I marked it to make sure that I don’t loose it this time!

Heretic,

the tips you gave,

“Apply a render tag to the glass w/ seen by GI unchecked..... chrome material under illumination uncheck for generating radiosity.... Shiny metallic objects, dark black objects and trasparent objects do not need to generate radiosity.... I'm sure your render times will greatly improve........”


Render times dramatically improved!

I’ve been tinkering with the Min & Max & diffuse settings. Your settings seemed low, but it appears that I don’t always have to set things as high as I imagined based on the defaults.


I started a new model. It has only one chair, a table, two walls and the floor to keep things simple so that I can hone in on how each setting affects the final image. I’ll post it when I get it presentable.

Thanks!

[FusionDG]

Well, I finished my first decent radiosity rendering. The scene is composed of 2 spline walls, a floor, the LC3 chair, and a table. The times were much better this time around, thanks to all of your advice!

http://www.fusiondesigngroup.com/pics/lc3redwall06.jpg

Coming in at 9:26 :) the following 1024 x 768 image was produced with the settings:

AA = Geometry/ Still Image
Radiosity
Stregnth = 100
Accuracy = 80
Prepass = ½
Diffuse depth = 3
Stochastic samples = 300
Min res = 25
Max = 150

Surface caustics = Y

Ray depth = 4
Refl depth = 3
Shadow = 4
Threshold = 0
Detail = 100

I probably could of used smaller settings on the min & max res, but at under 10:00, I’m happy. I’ll try lowering the settings and stop before the quality degrades.

Any other suggestions?

[FusionDG]

And the clean seat version [9:12 :) ]:

http://www.fusiondesigngroup.com/pics/lc3redwall07.jpg

[AdamT]

Looks really nice--great improvement. Are the caustics really adding anything? You might try a separate pass for caustics and check that out. I'd also use a prepass of 1/1.

The modeling and texturing is quite nice too.

[kiwi]

Nice pic :thumbsup:



I have gotten reasonable results with min setting at 10 and max at 40,with stochastic samples at 50 and the other settings pretty much the same as your other ones with prepass of 1/1 :)



Stu.

[FusionDG]

Thanks Adam and Stu.

I’ll do a render with your setting recommendations later tonight and post the pic. I’d love to get the time down from here!

The caustics were done on a separate pass. I liked them there, but I’ll post the two pics with and without and you can let me know what you think. I did the image with a HDRI to light the scnene. I used two spot lights only to get the specular highlights brought out in the leather. I also used these two lights for the caustics. The lights have a far clip & 50% brightness to restrict influence on the rest of the scene.

See ya later tonight and thank you for the kind words…

[FusionDG]

I just did the same render with the following settings and came in at 10:35 ?

1024 x 768 image
AA = Geometry/ Still Image
Radiosity
Stregnth = 100
Accuracy = 80
Prepass = 1/1
Diffuse depth = 3
Stochastic samples = 50
Min res = 10
Max = 40

Surface caustics = Y

Ray depth = 4
Refl depth = 3
Shadow = 4
Threshold = 0
Detail = 100

did the prepass make that much of a difference? I’ll run it again at 1/2

[kiwi]

Oh ok I thought it would have been faster :hmm: ,Your original settings definitely seem better.



I often just use geometry AA especially if I going to be adding depth of field into the image in Photoshop later by using g blur.



Have you tried it without the caustics at all?



Stu.

[FusionDG]

Well, here are two more pic tests:

This pic ran in at 7:47 with these settings:

http://www.fusiondesigngroup.com/pics/lc3redwall09.jpg

1024 x 768 image
AA = Geometry/ Still Image
Radiosity
Strength = 100
Accuracy = 80
Prepass = 1/2
Diffuse depth = 3
Stochastic samples = 50
Min res = 10
Max = 40

Surface caustics = Y

Ray depth = 4
Refl depth = 3
Shadow = 4
Threshold = 0
Detail = 100

Then this pic with the same above specs except no caustics came in at 3:54:

http://www.fusiondesigngroup.com/pics/lc3redwall10.jpg

about half the time!

But they both look a little splotchy in the wall corner :hmm:

[kiwi]

Ya they do look a bit splotchy eh :hmm:


If you go back to your original settings and dont use caustics it might be pretty close to the look you after :D



I think the thing with radiosity is that you almost always need a new solution for each image you render :) My machine is not fast enough to do too much in the area of radiosity tweaking etc.



Stu.

[FusionDG]

Hi Kiwi,

It seems that both you and Adam feel that the caustic reflection on the chair from the chrome are not needed. Do you feel that this effect wouldn’t be present in a real situation? I thought that it might, but maybe not? Maybe the non-caustic solution looks more true to life?

[AdamT]

I think the caustic reflection looks okay, but it also looks alright without it. I wasn't sure originally if the highlight on the chair was caustics or just a normal reflection of the metal.

[kiwi]

Just my opinion but I think the caustics looks a bit bright or soemthing.Cant quite put my finger on what it is.



To get that reflective quality I would try adding a little bit of random noise as a bump,only just use white make the black 50% grey and see if you like the result...that is if you are not sick of doing renders by now :D ...acutally I will see if I can make a quick shader for you as a base to start from :)



Stu.

[FusionDG]

I guess I feel the same way about the caustic to a degree. It looks ok, but something just doesn’t look proper. I feel the effect would be present, but maybe not as bright and sharper? :hmm:

Kiwi, I think I know what your talking about, but it would be nice to have that shader as a base to start from.

Thanks for the crits & help!

[kiwi]

Call me Stu :)


I am by no means an authority on how to make shaders,but I came up with this.The bump is a bit like rough leather as opposed to the smooth you are looking for,but it might give you some insight :)



Stu.

[FusionDG]

Stu ;)

thx for the tex. i looked at it quickly, but I'll take a more in depth review of it later this week when i get some time. Your tex should be a good case study for me to review.

Gotta get some things done now before the work week starts tomorrow!

thanks for your insights, they have been very helpful :)

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