New Mental Ray shaders development

[Maximus]

gonna post here what i posted there:

Running some tests with those new shaders.
Some highlights:

Subsurface speed is amazing, didnt expect it, also all the controls are very simple to get out a nice result.
Glossy surfaces in general, the speed here is incredibly fast when you increase the samples per-material which i didnt expect either, usually when you increase samples render times goes up, in this case it renders faster..
So far I really like those new shaders and setup, there are some things that are a bit weird and i'm gonna list them here:

1) As other people have noticed there is a "black" halo around reflective surfaces. Now, i tried to dig into this thing and found out that it is caused by the IOR. If you switch to "use directional weight mode 1" and control manually the "brdf" curve you can get away with no black halo, but this is quite a forced approach and not physically correct one. I believe those black halos shouldnt be there when using Fresnel mode (durectional weight mode 0).
In all David renders those halos are present, also there are present in the documentations, especially in the Car paint "tutorial" tryin to mimic mia_material car paint, and in the blue horse tutorial when mimic the blue mia_material horse.
Here are the 2 screens:


and the mila material


the other example:


and the mila again with halo



Would be nice to have some clarification on what is happening here, is it a bug or what?
Also it would be nice to have some examples of common materials setup, like a glass wine for example, a bunch of metals and some glossy surfaces, because at the moment there are quite huge differences with the mia_material we are all used to.

For example i rendered a simple glass sphere, it took quite double the time it took to render a standard mia_material glass, i have used 2 layers with mila, one mila_specular_reflection on top and one mila_specular transmission on bottom. Render times werent amazing compared to mia. Also it produced some noise i had to crank up the unified sampling to get rid of (didnt do the same with the mia_material). And I also had this black halo on the glass too. Here are couple of images i rendered:

Here you can notice still the black contour halo on the leftmost sphere.



This is a different view of the same scene where we can see a more pronunced subsurface effect. (halo on the glass too )



And here is a link with a screen of the render tree with the shaders for who wants to take a look on how they were connected.
http://img685.imageshack.us/img685/115/setupcf.jpg

[Daniel Brassard]

No magic Tekano, I just logged in and click the link to the ftp, that's all.

I use Google Chrome, no hassle, no fuss. Sent you a PM.

[Tekano]

well i have a forum account there, 2 in fact now, im logged in , am using chrome, but I still do not have 'privileges ' to see that thread or any other section inside of 'Layering-Library' - same thing happens when I try and click on the link that Maximus provided at the start of this thread. according to my view inside the forum I can only see threads to do with Mental Ray, Iray, Mental Mill, MetaSL and Reality Server. Nothing else. am sure you guys have access to beta section that normal login does not allow. there is no email or access to contact an admin to ask questions either. and they have the cheek to complain about Autodesk implementing things badly, I do believe there own forum is less helpful than AD's if possible...!

[Kzin]

well i have a forum account there, 2 in fact now, im logged in , am using chrome, but I still do not have 'privileges ' to see that thread or any other section inside of 'Layering-Library' - same thing happens when I try and click on the link that Maximus provided at the start of this thread. according to my view inside the forum I can only see threads to do with Mental Ray, Iray, Mental Mill, MetaSL and Reality Server. Nothing else. am sure you guys have access to beta section that normal login does not allow. there is no email or access to contact an admin to ask questions either. and they have the cheek to complain about Autodesk implementing things badly, I do believe there own forum is less helpful than AD's if possible...!

reed on elementalray that you have to write a comment in one of the other threads to make sure you are not a bot. bit strange, but you should try it.

[Daniel Brassard]

Here is a couple of threads on elementalray about the layered library shaders (although Mayacentric) still a good read.

http://elementalray.wordpress.com/2013/ ... a-shaders/

http://elementalray.wordpress.com/2013/ ... with-mila/

And some on the Material Description Language. A bit technical but all good.

http://elementalray.wordpress.com/2013/ ... -language/

and something to know:

http://elementalray.wordpress.com/2013/ ... g-library/

note:

You must be a registered forum user. Also, the forum does not recognize users automatically for spam reasons, you need to participate by making a post at some point. This also prevents Bots from swarming the board. Once the shader package is linked you may be able to make a post and download it.

Cheers!

Dan

[Tekano]

thanks Kzin and Daniel, ive made a post, awaiting admin moderation, if they are doing it this way what is the point of the ridiculous capcha thing, posting the url of the forum and answering elementary maths questions in the register form... sheesh!

[Maximus]

thanks Kzin and Daniel, ive made a post, awaiting admin moderation, if they are doing it this way what is the point of the ridiculous capcha thing, posting the url of the forum and answering elementary maths questions in the register form... sheesh!

sent you a pm

[Maximus]

anyone was able to set the string option "light relative scale"? cause i have no idea how to do it in softimage..

[Tekano]

and Im in..! now to read the docs! thank you Kzin for those simple instructions - you overwrote geoshader.h yes?

[rray]

Great to see these shaders work already out of the box. The "late" SI team obviously did a great job on the .mi import integration.

[Maximus]

they need the string option "light relative scale" to work properly. Textures and shading will be off if you dont use this, i've been there already. I'm trying to figure out how to set this within softimage because in maya you can easily do it with a string option.

Here you can see some test I did without this option and how the shading/texturing is completely off compared to mia material

http://img163.imageshack.us/img163/4568/compr.jpg

[Kzin]

they need the string option "light relative scale" to work properly. Textures and shading will be off if you dont use this, i've been there already. I'm trying to figure out how to set this within softimage because in maya you can easily do it with a string option.

Here you can see some test I did without this option and how the shading/texturing is completely off compared to mia material

http://img163.imageshack.us/img163/4568/compr.jpg

there is no need for such a light scale value if you use only mila shaders in xsi.
if you mixing mila and mia, then you have to set in mia 0.318 in diffuse weight instead of 1. the same when you render ibl and mia, but mila is rendering correct out of the box inside xsi.

[Maximus]

they need the string option "light relative scale" to work properly. Textures and shading will be off if you dont use this, i've been there already. I'm trying to figure out how to set this within softimage because in maya you can easily do it with a string option.

Here you can see some test I did without this option and how the shading/texturing is completely off compared to mia material

http://img163.imageshack.us/img163/4568/compr.jpg

there is no need for such a light scale value if you use only mila shaders in xsi.
if you mixing mila and mia, then you have to set in mia 0.318 in diffuse weight instead of 1. the same when you render ibl and mia, but mila is rendering correct out of the box inside xsi.

Well in that test i did it tends to darken the texture a lot, you can see the third render here : http://img163.imageshack.us/img163/4568/compr.jpg.
That is both mia and mila with one portal light. The texture shown in mila is completely off, on another scene i applied a multiply by 3.14 on mila diffuse texture and it rendered correct same as mia material.
Also it says on the documents you need to set this string options. So i'm quite confused.

[Kzin]

they need the string option "light relative scale" to work properly. Textures and shading will be off if you dont use this, i've been there already. I'm trying to figure out how to set this within softimage because in maya you can easily do it with a string option.

Here you can see some test I did without this option and how the shading/texturing is completely off compared to mia material

http://img163.imageshack.us/img163/4568/compr.jpg

there is no need for such a light scale value if you use only mila shaders in xsi.
if you mixing mila and mia, then you have to set in mia 0.318 in diffuse weight instead of 1. the same when you render ibl and mia, but mila is rendering correct out of the box inside xsi.

Well in that test i did it tends to darken the texture a lot, you can see the third render here : http://img163.imageshack.us/img163/4568/compr.jpg.
That is both mia and mila with one portal light. The texture shown in mila is completely off, on another scene i applied a multiply by 3.14 on mila diffuse texture and it rendered correct same as mia material.
Also it says on the documents you need to set this string options. So i'm quite confused.

mila is rendering correct, mia does not for things like ibl lighting, its a different shading convention. so if mila is darker, then increase the lighting intensity. if you mix mila with mia then divide your diffuse weight from mia by pi to get correct results compared to mila.

[Tekano]

which light type are you using Maximus?, it only seemed to work with Area lights and the soft light shader . the other light shaders I tried, (well 2 others) dont have that 'I'm an area light' toggle and seemed much dimmer without that area lights toggle on.

[Kzin]

which light type are you using Maximus?, it only seemed to work with Area lights and the soft light shader . the other light shaders I tried, (well 2 others) dont have that 'I'm an area light' toggle and seemed much dimmer without that area lights toggle on.

mila is designed for arealights and you should only use lights flagged as arealights like user_ibl and user_ibl_rect (rect is really fast now with mila), mib_photomatric or physical_light for example.
and i know, the old style presets in xsi does not make it that easy because presets are missing.