Messages

1

[Max] General Discussion / Re: Light diffusion material

« on: 2018-05-30, 12:39:15 »

It would be plausible in some light conditions, but for the specific light of that scene and a somewhat credible diffusing material, I would expect something more like the image attached in this post, which was rendered with bidir/VCM.

At least it should be possible to control the "blurriness" of light projection.

What I need is to understand physical light behavior with the help of corona (which I might be able to do with the experimental mode), use that knowledge to make project decisions, and only then try to make a final image for presentation purposes.

This final image might be difficult if I decide to go for something like 0,5 refraction glossiness, with real caustics, as in the attached image.

2

[Max] General Discussion / Re: Light diffusion material

« on: 2018-05-29, 19:43:38 »

There you go!

With bidir/VCM it works as expected. I will do some tests to better understand the usability of this method for my specific needs.

I haven't been following the forum closely for the last couple of years, but i'm a bit surprised that this isn't a more frequent issue tbh. Hope it can be brought to a production ready setup soon.

Thanks again for the help.

3

[Max] General Discussion / Re: Light diffusion material

« on: 2018-05-29, 16:52:04 »

I've replicated the behavior in several different test scenes (I'll attach one of them, but it's rather basic), and even went back to other scenes with normal glass windows and changed the materials, but results are the same throughout.

I thought about caustics as well (render times and noise are not a concern) but turning them on simply blocks any direct light from coming in, which doesn't seem plausible either. It's like you have maximum diffusion with no control whatsoever on the blur amount, even with different refraction glossiness values.
I also just did what you suggested, using translucency with no refraction, but it kinda does the same thing, as you are limited to 100% diffusion.
I guess this could be the case with some materials, but not necessarily with all of them, right?

4

[Max] General Discussion / Re: Light diffusion material

« on: 2018-05-29, 15:18:14 »

It has depth. I've played with that too, even to an exaggerated thickness, but it didn't change either.

5

[Max] General Discussion / Light diffusion material

« on: 2018-05-29, 14:25:42 »

Hello guys!

I'm currently developing a project where I need corona to simulate the light behavior of a slightly unconventional lighting system, and I'm doubting the results I'm getting in terms of it being physically correct.
The system itself will eventually have other layers of complexity, with LED lighting and sensors to mimic color and intensity of natural light, but for the purpose of this topic I'll go to the point.
I have a series of small/regular sized windows and, in front of them, I'll put some sort of light diffusion continuous plane to minimize the perception of the individual windows and create a more uniform strip of light.
In terms of direct visibility it will never be perfect using this diffusion plane only (hence the LED to improve the effect), but what I wasn't expecting was that the sun rays weren't diffused passing through it.
I'm using corona sun+sky (but I got the same results with HDRI) and I've played with all refraction, volumetric, sss and translucency values. The only thing that was constant was the defined shape of the windows projected on the ground. Shouldn't the light get diffused? is this normal behavior?
I made a quick real test with a laser and a polycarbonate panel and it did get quite diffused as I was expecting.
Am I missing something? Is it a known limitation?

Thanks in advance.

6

News / Re: New Energy conservation mode

« on: 2015-02-27, 10:17:58 »

Yes, totally right Rawalanche.
That's also how I found out to begin with... doing the usual matte light grey override material to check lighting.

Should we start a new thread specific for this?
Ondra what can we do to convince you to find a solution? and how can we help?

7

News / Re: New Energy conservation mode

« on: 2015-02-27, 09:05:23 »

Well, I've tried different types of geometry and always get the same problem, but I do find strange that it wasn't a big problem for everyone.
Could this be related to Max version?

I'll attach what I'm looking at...
Only change was legacy mode.

8

News / Re: New Energy conservation mode

« on: 2015-02-26, 22:47:02 »

While I do appreciate and totally support the will to maintain physically correct reflections, that's also the reason why Rawalanche is right to stress the need for some kind of solution. As it is, the new BRDF simply doesn't look correct and for me at least is unusable.
I would even suggest going back to the old model as default and make ggx an experimental one untill it's fully sorted out.
How wasn't this a bigger issue for everyone during daily builds testing?

9

News / Re: New Energy conservation mode

« on: 2015-02-26, 18:24:42 »

We're going offtopic here, but why didn't it happen with previous model?

10

News / Re: New Energy conservation mode

« on: 2015-02-26, 17:37:34 »

 Your explanation for the energy conservation was exactly how I thought it worked, and the reason why I associated the dark grazing angles with it. I looked like it is subtracting to much energy from diffuse and thus leaving the color of reflection only.

But now that i think of it, that behavior does make sense as it is... and if the issue is not related to the energy conservation feature, could it be that lowering glossiness is also lowering reflection intensity, making it redundant with EC? In the passes, it does look weaker, not only spread wider.

The falloff map issue, well, not ideal but it's not the end of the world either. Maybe some chart matching IOR values with 0° angle reflection values could help.

I'm still confident Ondra will find solutions.

11

News / Re: New Energy conservation mode

« on: 2015-02-26, 17:00:32 »

Oh, I see... Thanks for clarifying that.
I pretty much makes the new BRDF unusable in most scenarios then :/
I hope a solution can be found for it.

What about the falloff map thing? results are much better using it, and still different from legacy mode.

12

News / Re: New Energy conservation mode

« on: 2015-02-26, 16:28:27 »

Hey guys

Could anyone please elaborate a bit on the physical and technical reasoning behind the energy conservation feature?

It was most curious to try this out on the new Corona 1.0, but I only expected a slight darkening on reflections (as seen on this thread), and I'm actually getting quite drastic differences when I turn on/off the legacy mode, which I'm not totally convinced to be correct. Of course I could be wrong, but that's what my eyes are telling me at least.

I did a few tests to try to understand the issue better, and also to see if ggx had anything to do with it.

- Created a simple scene with a ground plane and a couple boxes lighted by corona sun
- Applied a white material (180RGB) to all objects and positioned the camera at an angle to increase reflections perception
- Reflection 1, IOR 1.52, Glossiness 1 (slight difference between legacy on and off as initially expected)
- Reflection 1, IOR 1.52, Glossiness 0,1 (huge difference between modes, with reflective faces much darker than expected)
- Reflection 0 (to compare to those same faces, and reflection is effectively darkening a lot when glossiness is very low)
- also tried a fallof map to control reflection instead of IOR, but i looks pretty much like legacy mode (without ggx), so I figured energy conservation isn't working with that.

So is it normal/correct that a low glossiness reflection is so much darker than a high glossiness one? or could this be some kind of bug?
even without.

13

Hardware / Re: New workstation

« on: 2015-01-09, 18:23:00 »

Case closed then.


I figured xeons would be pricier to get identical performance, but those numbers really make the choice easy!   

X99-Pro it is then.

I can get the AX760 for an additional 40€, so it's no problem at all. Wasn't trying to save really, just being ignorant ;)



Will let you know how it goes when it's ready.
Thanks again Juraj. I'll buy you a beer if you'r ever in Portugal!

14

Hardware / Re: New workstation

« on: 2015-01-09, 16:23:12 »

Hi Juraj,
was looking forward to your feedback, and it is much appreciated.

For years I've been a Macbook Pro user at home, so it's my first personal machine for rendering purposes and I'll take your advice on investing in a powerful one to start with.
Since you haven't commented on the Xeon possibility, I'll assume core i7 is the way to go here.


Other than that,
 
my preferred seller doesn't seem to have the X99-S, but has good deals on the X99-PRO and X99-A... how does the PRO compare to the S?;

will check the Fractal KelvinS36 + Arc solution out, but I'll probably go for the Define + NH-D15 if you say it's good enough cooling (what do you gather would be a safe clocking for the 5960X with the NH-D15?);

4x Crucial DDR4 2133 8Gb to save quite a bit and invest on a bigger HDD as suggested;

PSU - again, I have a good deal on a Corsair RM750w, which seems to fit the criteria.

15

Hardware / New workstation

« on: 2015-01-09, 11:25:45 »

Hey guys
so, after some time using mostly stations from the studios where I've worked, I've decided to invest in a personal machine.
I did some research, but since I'm no expert, thought I would ask for some advice.

My most demanding work is rendering (3ds+corona), the rest being mostly autocad, photoshop and indesign.


Here is the setup I'm considering (with a slightly stretched budget already):


CPU: Intel Core i7-5960X
cooler: Noctua NH-D15
motherboard: Asus X99-DELUXE
graphics card: Asus STRIX-GTX970
RAM: Gskill Ripjaws4 Black DDR4-2400Mhz 4x8Gb
1st Disk: SSD Samsung 2.5" 850 Pro 256Gb
2nd Disk: WD Black 1TB SATA III 64Mb
case: Fractal Define R5


a couple of question/doubts:

is the cpu investment (1k+€) worth it? or should I settle for the 6core version? should I  consider xeon?
which PSU would you recommend? (I'm a bit lost on this one)
regarding RAM, should I go for DDR4 2133 instead of the 2400, since the cpu is supposedly designed for it?



thanks in advance
Fabio