mental ray interior daylight scene

[Fran]

Originally posted by joseph alexander:

Fran,

I think you need a more severe falloff, the room seems completely evenly lit. That's what's so nice about your other renders, you obviously have control over contrast, in fact mastery, these don't achieve that yet. I think as soon as you figure out how to get the back of the room dark and the front light, the renders will start to take shape.

Hi Joe,

 

Thanks for that! I'm so used to photometric lights that I'm a real dummy about attenuation. I've attached a quick test. It's extreme, but still a starting point.

 

 

Originally posted by joseph alexander:

(thanks again for the power translators help)

No problem. I think we're even.

[joseph alexander]

nice. I think the whole room will look really good with that kind of contrast. Also, this is just my personal opinion on stuff, but filleting the edges of your tables and edge trims will add a nice edge glare, i think its 'filletedge' in rhino. I know with some of your renders the sharp edges are a cg giveaway, like with that table in the foreground.

 

-joe

[ch83575]

Great work Fran! I love your website and all of the images on it.

 

I use MR in Maya but I am sure the ideas are the same, just with a few differences in exicution.

 

From looking at your previous works I would have thought that you would be better off relying mostly on Final Gather than GI. The GI is certainly necessary in a scene like this to help the main illumination penitrate deep into the room. BUT, the look of a mostly FG render instead of a GI render is much more your style.

 

One specific example: The hanging lights, the back sides of them look like they were rendered in Max3 with the scanline. I mean they have no GI effect at all. With the final gather they would sample the brighter wall behind them and take on a nice smooth look.

 

My thought would be to start with no GI and just FG (the back of the room will be very dark. Get your lighting looking balanced and smooth, then turn on GI and start to push more light into the back of the room with the photon projection. I know that that is backwards from what most people say, but it is what i do and it seems to work for me.

 

Also, your rendering times sound outrageous! Off the top of my head I would have thought that a 800x600 like those in your post should have taken 20min at the most. Maybe i am off because i have been concentrating on exteriors lately, but I just cant believe 1h27m. Maybe its a Max thing .

 

Keep up the great work!

[Fran]

Originally posted by joseph alexander:

I know with some of your renders the sharp edges are a cg giveaway, like with that table in the foreground.

 

-joe

Just a heads up for ya Joe, this is cg. But seriously, you are correct, sometimes I just don't want to fillet everything even now that I know better. You couldn't know this, but that's not a table, it's a box that's one of a series. I'd placed them in the scene thinking that the attenuation was going to be so subtle that I'd need them there to see the difference. Yeah subtle.

 

[Fran]

Originally posted by ch83575:

Great work Fran! I love your website and all of the images on it.

Thanks Chad.

 

Originally posted by ch83575:

BUT, the look of a mostly FG render instead of a GI render is much more your style.

Has anyone considered that I might want "the look" to be different? That maybe I don't want "the look" at all?

 

Originally posted by ch83575:

My thought would be to start with no GI and just FG (the back of the room will be very dark. Get your lighting looking balanced and smooth, then turn on GI and start to push more light into the back of the room with the photon projection. I know that that is backwards from what most people say, but it is what i do and it seems to work for me.

Thanks, I'll try that.

 

Originally posted by ch83575:

Also, your rendering times sound outrageous! Off the top of my head I would have thought that a 800x600 like those in your post should have taken 20min at the most. Maybe i am off because i have been concentrating on exteriors lately, but I just cant believe 1h27m. Maybe its a Max thing

In a follow up post, I stated that I was able to cut render time in half (from 1:27 to 0:44) by reducing the area light samples. Another thing I'm suspicious of is bitmap materials and how the max interface writes out the scene file. I don't think bitmaps are being handled in an optimized fashion. Procedural textures seem to render faster - which is bass-ackward.

[ch83575]

MRs bitmap pre-filter is second to none, and probably the fastest in the industry, so the idea of it not handling bitmaps well is concerning. I do know that MR doesn't really like jpegs. When i moved to MR in Maya 4.5 I switched entirely to BMP, but the difference wasn't dramatic, just noticable.

 

Sorry i missed the sampling thing cutting the render time, but it still seems too long. FG would allow you to lower it even more and still look smooth (dont get me wrong though, FG is NEVER a time saver!), maybe even smoother and more natrual than before.

 

Do you have access to MRs "physical light" node? If you do you should experiment with it. It is kinda like photometric lighting in max, but much better in my eyes. I quite often use it as a sun with no extra fill lights, just FG and GI. Just another idea.

 

Have fun with MR!

[Fran]

Originally posted by ch83575:

Do you have access to MRs "physical light" node? If you do you should experiment with it. It is kinda like photometric lighting in max, but much better in my eyes. I quite often use it as a sun with no extra fill lights, just FG and GI. Just another idea.

Max doesn't appear to expose the physical light shader. It supplies the 3 light shaders (infinate, point, spot), but no photon emitters so you can't do GI with them AFAIK.

 

Max does support custom shaders though. Do you know of any of that type available? I have tried coding a simple phong shader and couldn't get it to compile (VC++ 6.0).

 

Thanks again.

[joseph alexander]

just a question with MR for max 6, with GI, do the photons pentrate through glass?

with brazil this has been a big problem for me because gi photons don't go through things that are transparent. (there's ways around this but all of them are kind of a pain)

anybody know if this is true for other programs like vray or final render? like if there's an option to allow photon permiability?

 

-joe

[ch83575]

MR has a built in "compile on the fly" compiler that links custom shaders at runtime, but with maya I think you need to have a standalone licence to use it, but maybe max is different. Most of the time the problem is now with the compiling, but with the registration. Each custom shader (or shader library) needs to have the .mi shader and the .dll linked in the .rayrc registry (this is all for Maya, but i am sure it would be the same with max).

 

Mental Images has a FTP site with all of their standard shader library available to the public, maybe you could dowload the physical light and use it like a custom shader(?). Its probably not worth the effort in the long run, but it is cool.

 

Does this mean that you do not have access to the MR physical shaders like DGS or do you get those but have to run them in phong aprox. mode?

[ch83575]

Originally posted by ch83575:

Most of the time the problem is now with the compiling, but with the registration.

I ment "not", not "now."

 

wow does that look confusing

[ch83575]

Sorry for the 3 in a row, but I forgot to answer Joe.

 

Yes, photons can go thru glass. In Maya by default they go thru in direct relation to the trancparency and translucence (some fancy combination of the two actualy) but that can be overrode by aplying a photon shader to the material. That flexability basicly gives the user an infinite possiblity of combinations to control your photons, you could even have photons pass thru opaque objects in any complex relationship you can dream up (that is if the mood struck you). Actualy thats the whole idea behind MR!

 

(can you tell I love MR?)

 

Chad

[Fran]

Hi Chad,

 

A little follow-up on the bitmap optimization issue: I did some test renders on a sample scene provided with the max installation. Here are the results (for a 740x400 pixel image):

 

4min 42sec with bitmaps

2min 31sec without bitmaps

 

That's waayyy significant isn't it? The bitmaps in question are tif, but converting them to bmp actually added a couple of seconds to the render time. :???:

[xgarcia]

Fran - what about using them as jpegs? Any time savings? Just curious.

[Fran]

Hi Xavier,

 

If anything, mr doesn't really like jpegs, and I think it won't use progressive jpegs at all. I use jpegs with mr, but the render time isn't very much better with tga, tif or bmp. Since most of my material library is in jpeg format, I haven't bothered to change them over.

 

Didn't you render the sample scene that came with max6? Did you say it took 57 minutes? I was surprised when it rendered in 11min 27sec on my machine (Athlon xp 2400, 1.5 gb ram).

[xgarcia]

Yeah, but I had changed the camera angle and turned on the DOF. The camera that loads with the scene took around 20 minutes on my 1900XP. here is the thread.

 

Thx for the jpeg info.

[izrut]

Hello Masters of 3d world

 

I need your advice...

Here is a siene posted in other forum that I did some testing.There are no textures (only the windows are with raytrace), tell me how to optimize it pls - faster render time and realistic non-textured view

 

10x in advance

[slipknot66]

Hello Fran

 

First i need to say that i really like your interior designs, its perfect

Well.. about MentalRay i will try to help, with some sugestions but im using Maya,and im still learning..so...well... when i render interiors usuallly i create a point light and convert into mrarealights with square projections, not sure how mr handles max lights,i use the same aproach as Vray light which consists of a point light with a square projection generating softshadows. and i think the use of FG can have a huge difference in the way shadows are generated, of course the render time will be really slow. and for the sun light i use a directional light with raytraced shadows with no photon emittion.. well.. i hope this information can help you.. but as i said .. im still learning too.Again i really like your interior designs, i wish i had the same good taste as you have to create and compose the interiors but..im not good at that..lol

 

Sorry about english... just wanted to help..

[joske]

I did the bloom in Photoshop with the diffuse glow filter (Filters->Distort menu). I set Grain to zero and Glow to 6 or so and Clear amount to 18 or more.

 

if you want to, this effect can be done inside max/viz also... just put the glare shader in the renderer/camera effects/output slot

you might have to unlock the glare shader first

it has the same effect on the bright areas in the scene, but might give a little more control than the post glare in photoshop...

[joske]

Hmmm....sadly we had no sun today, just a nice ambient fog light, so i can't look at it. Still a bit irritating for me to get a shadow from a nearly horizontal shining light while the sun shines from a higher angle. But if you insist on it

 

i don't know what planet you live on , but on mine it's exactly like that in real live dude, lol just messing with ya...

 

no really : you got 2 main light sources in reality, the sun + the ambient light

outdoors the ambient light could be like a skylight omitting shadows in all directions

indoors this ambient light gets 'channeled' trough the windows

so even if the sun is completely blocked by the clouds, you will have the ambient shadows inside. it doesn't matter where the direct and indirect sunlight falls inside or witch direction the sun is shining, you will allways have the ambient shadows (even in area's like 10 meters away from a window for instance), and they will be parallel to the window

however the lower the intensity from the sunlight, the harder the ambient shadows are.

So you could argue that Fran's ambient shadows are to dark... but just look in your own house, the are allways dark like in Fran's renders.

 

in max/viz however the 'skylight' is almost useless for interiors, hence the most common workaround :

area omnis or spots (the size of the windows or bigger) infront of each window.

and if you analyse your own room, (windows = large area lights) this would be the most 'real' workflow to simulate the ambient light in reality. than just add a spot for the sun and let mental ray do the rest for ya...

[joske]

 

Juan Carlos:

As for shadows, you can't do soft shadows with a directional light unless you use a shadow map. The map has to be huge in order to eliminate light leaks. All this fill light and shadow manipulation is very new to me, so it will take time and good advise to get it right.

 

[ December 01, 2003, 12:59 PM: Message edited by: Fran ]

I forgot to mention that I decreased the samples on the area lights from 12 to 7 and render time for this view went from 1hr 27min to 44min 19sec.

[ December 02, 2003, 11:33 AM: Message edited by: Fran ]

 

well : i allways use a Mr area omni in front of my windows, and i do use a raytrace shadow with simular results as your shadow maps Fran, just remember to turn up the area to a size bigger than your windows

 

as for the light sampling, yes look at this example for an idea of the trade off between smoothness and rendertimes :

http://www.cgarchitect.com/vb/attachment.php?attachmentid=426

 

i donnow if you used Fgather or not but this might speed up things a bit :

you might have faster rendertimes when using slightly bigger and less photons

and lower light samples, with just a very small Fgather to smooth things out again (not more then 50-100)

 

hope i could help with this

[kicks]

philip,

[joske]

wel to be hounest i read somewhere Mray only can handle raytrace... but people like Fran have prouven that's definatly not the case

So i never really tried all the different combinations (stand omni, mr omni, raytrace, shadow map,...) i just went for the obvious mr area omni and spot, with raytrace all the time, and it works for me.

Just give it a try patrick... if it looks good...it is good i would say and mabey you could even squize a few secs off the render times??

[jildh]

So Fran, 7 months later... where are you at with MR? Did you return to Scanline/Radiosity? Could you get a 'warmer' feel with MR?

 

We just purchased Viz2005 upgrade this week and I'm doing some testing. For me the main disadvantage is that I can get that 'warmth' that I achieved using Default Scanline w/ Radiosity. I've seen that even Vray doesn't have that. Brazil renders look better but I don't access to that beauty.

 

What have you discovered in these 7 months?

 

Jorge.

 

 

BTW, I'm the Panamenian from McKinney Internacional you helped last year with a render.

[Fran]

Hi Jorge,

 

After 7 months I tried only one more scene with mental ray, which was several months ago. I just don't like it. There are things that are lacking with Radiosity, but I have never gotten past the "play" stage with anything else. I always go back to radiosity for production work.

 

Thanks for asking. Tell Art I said "Hi".

[lucho]

Hi Fran:

Is very nice to see a "work in progress" with the quality of your renders, i mean is really a class of how to make good renders, your work have impressed me so much.In fact i am learning a lot with this post.

Congratulations

Luis Calatayud

Architect

We want to see the final work