New Mental Ray shaders development

[etmthree]

1 si unit is 10cm, so 10 units are 1 meter, thats the global value. all lights should use the correct falloff with exponent of 2. dont use the photographic lens shader and all is fine with scaling of lights. keep also your scene in realistic units then you dont have problems.
if you use the mia_photometric light shader then you should set the cd/m1^2 to 10000 and units to meter scale to 10.

Yah, I got that. I've made a LOT of people unhappy with me for insisting they scale scenes of real-world objects to 1 SI unit = 1 decimeter. I also always use inverse square falloff for non-focused lights. I have only ever used an exposure lens shader under extreme duress -- they are Satan's work in softimage! ;-)

I'm glad to hear that the photometric light shader is in cd/sq._meter (of course there is no intensity slider, much less anything labeled CD/sq.m). However, the photometric light shader also does not like values over 1000.

I guess what I'm really asking for is either a slider calibrated AND LABELED in some real-world unit like cd/sq.m as well as consistency across the various light shaders. I'm quite sure this will never happen in an AD product.

[etmthree]

rendertime with ibl_rect is way to long, especially compared to exact fg with 128 rays.

again, the tests i did showing that ibl_rect is 2 to 3 times faster then physical light because of the light IS.
but cant really say something to the test without to take a look on your scene to see whats going on.

When I have used ibl_rect in the past with non-MILA shaders (mostly using Felix Geremus's Advanced Archmat), I have also seen much faster and noise-free renders. That's part of my surprise here.

Don't judge my renders by absolute time, as my kit is hopelessly aged (2008 MacPro). Here's the benchmark on it:
http://www.cpubenchmark.net/cpu.php?cpu ... Hz&id=1237

[Kzin]

to get the framebuffers out of mila in si:
open scene render option, go to available channels.
then add new channels named like david wrotes in his elemental blog:

direct_diffuse
indirect_diffuse
direct_glossy
indirect_glossy
direct_specular
indirect_specular
diffuse_transmission
glossy_transmission
specular_transmission
front_scatter
back_scatter
emission

all as color type. then add them in pass option in the render channels output and si will ouput them.

[etmthree]

Thanks, Kzin.

Do you know of a way to get the # of samples diagnostic output to work? I haven't managed that yet.

[Kzin]

Thanks, Kzin.

Do you know of a way to get the # of samples diagnostic output to work? I haven't managed that yet.

the buffer is called: mr_diagnostic_buffer_error

usage is the same like above. of course you have to activate the "view sampling" option in rendersettings/diagnostic.

[gustavoeb]

Hey Kzin, this is GREAT!
Thanks for that...

[Daniel Brassard]

to get the framebuffers out of mila in si

Thanks KZin. I was actually asking myself how to get the framebuffers out with SI. I thought I had to use the string options LD, LE, etc.

This is much simpler, the information is very timely. Did you put this information of the Mental ray Advanced forum as well? If not, I would suggest you pass it along as this is useful information for the other Dev as well.

Dan

[Kzin]

I would suggest you pass it along as this is useful information for the other Dev as well.

Dan

yes, i posted this also in the "Layering Library in Softimage?" thread in mr forum.

the good thing is, it means there is a direct connection to mr framebuffers in si, you only need to know the name of the framebuffer, put it in the list and you can output it directly.

mila does not need implemented natively in si with every update for framebuffer stuff (the biggest fear i had). and we also dont need custom framebuffersetups in rendertree which makes the usage alot easier and more independent.

[Daniel Brassard]

Thanks Kzin, I just notice your post on MR Forum. I should have check!

I am working on MetaSL shaders at this time, so did not have the chance to test MILA deeply but I like the principles of layering. I am looking at transferring some of the knowledge of MILA to MetaSL.

MetaSL in the other hand is PITA. In Soft2013, we still have specification 1.1.6. Hope Soft moved to 1.2.2 as we are missing some good types, functions and methods (Color3, transform_to_local, etc)

It look like some thing are also broken in Soft interpreter as some shaders only show inputs (althought the code clearly show outputs). I found some solutions for some of them thought.

I would like to also access the geoshader attributes, but that is for an other time. I may have to go native C++ for that.

Thanks for your contribution to the MILA shaders. Your comments are very much appreciated.

Dan

[Daniel Brassard]

Update to layering shader library as of 5 April 2013. Two packages, one for 3.10. and one for 3.11.

Fixed in this version (updated April 5):
-glossy transmission lobe now matches glossy reflection lobe
-documentation updated with input argument changes in previous patches, and now includes examples

Fixed in previous versions 3.10.3.18/3.11.2.1 (updated March 12):
-scatter component, rgb all detected for maximum sample radius
-glossy reflection/transmission changed to use quality instead of samples
-bump flakes, significant experimental changes, looking for feedback
-two versions, one for 3.10 and one for 3.11
-please note that the doc is not up-to-date with these changes, in particular the car paint Phenomenon

Fixed in previous version 3.10.3.17:
- components render by themselves for shader ball rendering (note that currently the max gui declarations supplied separately in max thread)
- ao colorbleed issues fixed
- default ray cutoff much smaller, won't lose energy for high ray count glossy samples in first hit
- transparency weighting should be more consistent (still possible issue with alphas)
- more passes available, and specular transmission light passes split off

Fixed in previous version 16b:
- dark edge falloff for specular/glossy traced reflections
- roughness exponent, now actually a power exponent of roughness before translation into brdf usage, a value of 1 should match iray
- Mac OS X linkage, possibly fixed with restructured code

Known issues in this version:
- glossy roughness and roughness exponent curve control will continue to be tested for potential modification (this version has correct direction for roughness_exponent, and default of 3, better, probably somewhere between 2 and 3 should be default)
- glossy transmission usage may cause crashing issues on Linux
- mila_bump_flakes not documented, and will continue to be modified for noise pattern reduction/changes
- transparency and LPE specification not fully implemented as planned, and documentation is a bit out-of-date, for example "L<RG><TS>+E" is how you'd see direct glossy light through one or more specularly transmissive surfaces, most likely transparent
- documentation of recommended Lighting needs rewrite, and Framebuffer discussion not finished
- missing mila component code example
- components by themselves plugged directly into a material will cause a crash. This crashes when making shader ball images in 3ds max, for example.

The package comes with documentation, and we'd like to involve the community in helping us refine the documentation, so I'll start posting up some of the documentation here to start the process.

Last edited by bart; April 5th, 2013 at 12:06. Reason: update

The updates are available as per the original thread location.
Nice!

From Bart at NVidia Advanced Forum:

Just put up a new download (April 4) that makes glossy transmission lobe match the glossy reflection lobe for the same roughness value.

Also, updated the doc a little bit with car paint Phen etc., matching the current layering.mi. However, now thinking I will change some of the defaults and naming of car paint to better serve these shaders, and future work, rather than match the older car paint terms. More in the paint flakes thread.

Next download in a week or two will have some input argument name changes, just giving out a word of warning now. Hoping that will be the last name changes before a first release, and able to focus on bugs, etc. for that release.

Known issue working on right now is the alpha for a transparent beauty, including going through multiple levels of transparency. Also, trying to assess exactly how to address propagate alpha, when using mila_specular/glossy_transmission. Its more complex now as a non-monolithic shader.

Cheers!

[Fer]

Waiting for MR 3.11 to test these babies. Hope Light importance sampling and MIS play nicely with these shaders.

[Bullit]

So this needs 2014?

[Kzin]

So this needs 2014?

no, the mila shaderpackages are available for mr3.10 and mr 3.11 so you can use them also in 2013.

[Bullit]

Thanks.

[Falam]

I asked this question on the nvidia forum, didn't get an answer as quick as I wanted, and a tad lazy to search this thread Here was my question;

The docs state

Two Reflection Nodes
One Refraction Node
One diffuse node

There are more then one reflection node which two do I plug into the layer node and which MILA layers node do I use ? I tried MILa_mix and Mila_layer, I can't plug any reflection\refraction node into either any of these layer nodes?

[Kzin]

I asked this question on the nvidia forum, didn't get an answer as quick as I wanted, and a tad lazy to search this thread Here was my question;

The docs state

Two Reflection Nodes
One Refraction Node
One diffuse node

There are more then one reflection node which two do I plug into the layer node and which MILA layers node do I use ? I tried MILa_mix and Mila_layer, I can't plug any reflection\refraction node into either any of these layer nodes?

you have to use a mila_glossy_reflection node or mila_specular_reflection node and not the old mib nodes.