Radiosity settings


#1

I know this has been debated before and i’ve read every thread and tutorial about it (well, almost…).

A friend of mine showed me a vray render and i wanted to show him how c4d could do that as well.

Here’s the vray render:

Notice the render time.

And here’s what i’m getting with C4D:

This was rendered in 12 minutes (Dual Xeon 2.2Ghz, 512 Ram) and i’m still not that happy with it, there are still some artifacts.

Radiosity settings in C4D:

And here’s the C4D (8.2) file:

Room.zip

Any help would be welcomed.
Thanks in advance!


#2

well to start with in order for you to play around and get the overall lighting feel, lower you min and max a whole heap, bring em down to min 1, and max 20 for instance, that will help while tyring to set it up. once your’e there you can up them some to try and get that shadow detail back in there, don’t forget to up the samples relative to them too.

next is your sky affecting the gi like his is? because it doesn’t look like it is. make sure your sky is allowed to affect the gi you will see a marked improvement, possibly don’t use a sky but use a large sphere object too, this will speed things up some while trying to get the overall lighting.

you also don’t have to bounce that many time with the diffuse depth, bring it back down to 3 while you’re working on it.

how many lights in his scene? make sure you have the same, and in the same place.

then play around with the materials, in their illumination tab, under gi recieve and gi transmit. if you up the transmit factor then the light will bounce “further” without washing things out as much.

hope some of that helps.


#3

Originally posted by mdme_sadie
lower you min and max a whole heap, bring em down to min 1, and max 20 for instance

actually you should never set your min too low as it slows down the render (the GI engine has to decide where to put that single sample and while it buggers around trying to decide where it should go it could have already placed in several shading points if it knew it was allowed to).

min is scene dependant of course but as far as i remember between 10 and 20 samples gives the best render times.

cheers, simon w.


#4

Thanks for the quick reply.

I’m not sure i can replicate the light settings from vray, since it uses some light portals on the windows.
The closer i get to that in C4D is area light which gave me some even worst results.
Light portals in vray work as rectangular light sources.
Maybe i can use some geometry with 100% luminance and a compositing tag to make it invisible to the camera. Not sure it’ll work though…

Anyway, thanks a lot for the tips! I’ll give it a try as soon as i can and will post some results.


#5

Hi all,
just quick test.

Sun Light+Sky

Render 7 min 16 sec

Gerri


#6

6 minutes and 20 seconds on my G4 PowerBook 1ghz. I think i might need to increase the samples…or at least some texture maps to reduce the noise in the shadows…


#7

This was an experiment using the existing light setup, but changing the Rad settings and increasing the “generate GI” setting of the room material to 150%. Render time was under ten minutes on a dual 2.4 Xeon.

Radiosity settings:

I prefer Policarpo and Gerri’s renders though. They don’t blow out the highlights like mine does.


#8

4minutes, 46 seconds with a little 512x512 texture map with noise added to the walls.

i am just learning C4D…so thanks for the file…


#9

Also, Viz definitely has one of the best–if not the best–radiosity engines out there. Unfortunately it costs as much as Cinema + AR, and you still have to buy Max. :frowning:


#10

Policarpo,
What are your radiosity settings? Did you change the lighting?


#11

and at 6minutes 43seconds I am pretty happy with it.

i’ve only been using C4D for about 10 hours so I am not sure where to cut corners and such…but I am really liking the speed of the rendering engine…so expect more progress from me as I learn to tweak every last bit of quality out of it as i learn to exploit its speed.

:beer:

I just turned on the Omni Light (20% brightness) and changed the color of the sky to a nicer blue.


#12

Cool–looks great. A little annoying that you’ve only been using Cinema for 10 hrs. and your render looks better than mine, but… :slight_smile:

Seriously though, it is really hard to get decent radiosity results in Cinema without using standard lights in addition to material illumination. And to be fair, the Viz render apparently also used lights.


#13

Heheh…thanks.

It’s like I always say. In the end what matters most are fundamentals. Once you know how a thing is supposed to look, you can push buttons in any application to get the results you want. And the buttons you end up pushing are the one’s which belong to the app which gives you high quality results faster.

Oh and…did I mention that I am only using the 8.2 demo. :drool:


#14

Thanks guys!
I’m impressed with some of the results!

Adam, the original image wasn’t rendered in Viz. It was rendered in 3dsmax with Vray, which i think is the only serious alternative to C4D in matter of speed and quality.

I have a friend who owns 3dsmax and Vray and he’s doing some experiments with the scene. I’ll post some results as the scene evolves.

Here’s a newer render:

The render time is still very low and that blurred reflection on the floor is just great! I wonder how C4D would handle that… blurred reflections take forever to render (or is it just me?).

Thanks a lot for all your input!
Keep it up


#15

800x600 render in 7minutes 30seconds on my G4 PowerBook 1ghz.

:eek:


#16

Now we’re getting somewhere…

The difference between both wood floors is considerable.
The floor in the vray render appears to reflect only the light or luminance.
I think this can be achieved by increasing the reflection blurriness in C4D, at the expense of render time, although i’m not sure it will produce the same results.

Anyone has a clue? This kind of reflection always amazed me and it’s one of the reasons i find vray renders so damn good!


#17

let me see what i can do.

damn…i wish i wasn’t using the demo…i could save my tests for you guys. :smiley:


#18

Originally posted by AdamT
Also, Viz definitely has one of the best–if not the best–radiosity engines out there. Unfortunately it costs as much as Cinema + AR, and you still have to buy Max. :frowning:

Mental Ray’s GI (which is actually based upon lights and not camera, so it’s radiosity, while Mental Ray’s version of our algo is Final Gathering) is way better :wink:


#19

I believe that Vray is the successor to Viz, but I could be wrong.

Yeah, blurred reflections do take forfreakinever in Cinema. Better to use reflection and object passes and blur them in post.


#20

Originally posted by ThirdEye
Mental Ray’s GI (which is actually based upon lights and not camera, so it’s radiosity, while Mental Ray’s version of our algo is Final Gathering) is way better :wink:

Could be, but I’ve never seen a head-to-head test.