The iray cometh

[LinchpinZA]

this is a long story, iray is using the internal builtin shaders (builtin_architectural is the mia_material simplification), those shaders assume the light is irradiance, but most traditional light shaders don’t return irradiance, but rather irradiance divided by pi (the average radiance for diffuse surfaces)
mia_material and the daylight system are built to work in the old way, so there is a discrepancy between the two systems
obviously in an integrated version of iray all of this should be under the hood, but…

this is also why i’m using this with IBL when using mia_materials:
setAttr -type “string” miDefaultOptions.stringOptions[31].name “environment lighting scale”;
setAttr -type “string” miDefaultOptions.stringOptions[31].type “float”;
setAttr -type “string” miDefaultOptions.stringOptions[31].value “0.318”;

if you use iray you need to change the value to 1.0

Hi Dagon,

Thanks for this useful post. I’m using an IBL testing iray. I was just playing around and I noticed changing the ‘environment lighting scale’ string has the the same effect as adjusting the color gain for the IBL node (using maya here). Are there any differences between adjusting these two variables?

Also should you multiply direct lights and indirect lighting( IBL) by 3.14 when using iray ? I understand the reasoning behind multiplying your lighting by pi when using iray, but theres one thing I don’t understand this magical multiplication of ‘3180’. I’m saying this after seeing your lighting scale of 0.318.

Off the topic of iray, I see this multiplication of 3180 used alot with creating HDR scene lighting. For example djx’s sun&sky script automatically multiplies the rgb scale of the physical sky by 3180 taking it from the default rgb scale of 0.0001 to 0.318. There was also a thread a while ago where people were testing the physical correctness of lights in maya, and they found that multiplying the intensity of lights by this number ‘3180’ gave the most physically correct result.

I have since been using this as a base for creating HDR scenes, multiplying my lighting by this number and leaving my cm2 factor in my exposure photographic shader set to ‘1’. I have never quite understood the reasoning behind this. Would greatly appreciate it if you could explain this for me.

-Chris

[chuckie7413]

Hi guys,

I am getting back into iray testing and trying to render some old interior scenes we did just with final gather.

One of my issues is with textures.

Before all textures had maya gamma correct nodes flugged into them to linearise them. However these nodes do not appear compatible with iray.

Can I ask how others have rendered their textures for linear workflow? Have you just coverted them to linear in photoshop/nuke first or are you able to get a gamma correct node/mip_gamma_gain node to work with iray?

Many thanks,

Richard

[TearGasJazz]

Hi guys,
I am getting back into iray testing and trying to render some old interior scenes we did just with final gather.
One of my issues is with textures.
Before all textures had maya gamma correct nodes flugged into them to linearise them. However these nodes do not appear compatible with iray.
Richard

If using Maya 2011 you can simply put Input to say sRGB, meaning that all your textures you plug in are handled as gamma corrected, which is the same as using the gammacorrect node.
Then under Output, you put it to Linear. Using a exposure_simple node on the camera is recommended with gamma set to 2.2.

The 3ds Max 2011 Subscription Package obviously comes with iRay support, and by support I mean some kind of GUI to control it all, at least thats what I heard.

[SePu]

but for color swatches you still have to gamma correct them right? for mia material, etc … I dont think the color management take into account color swatches … I might be wrong, correct me if I am…

Also do you still need to add the mia exposure simple even when you use the color management?
what I do when Im in the render view I go to Display > Color Management then

Image Color Profile > Linear
Display Color Profile > sRGB

Im wondering if with this setup you still need the mia exposure …
thx.

[rBrady]

I am copying this from the maya 2012 thread.

Got iray working in 2012

Seems much improved over all. I haven’t pushed it too hard but it seems they have made noticeable improvements to iray.

Here is how I got it working,

Copy the required dlls from another package that has iray with mental ray 3.9 (max 2012 in my case). Put them in the your maya2012\bin folder.

cudart64_32_7.dll
libiray.dll
libiraymr.dll

Now iray is installed, to activate it I use a slightly modified k_progressiveRendering script written by Sylvain Berger. I attached my version if his script.

Works fine on my 2 x gtx470 rig.

[TearGasJazz]

I am copying this from the maya 2012 thread.

Got iray working in 2012

Seems much improved over all. I haven’t pushed it too hard but it seems they have made noticeable improvements to iray.

Here is how I got it working,

Copy the required dlls from another package that has iray with mental ray 3.9 (max 2012 in my case). Put them in the your maya2012\bin folder.

cudart64_32_7.dll
libiray.dll
libiraymr.dll

Now iray is installed, to activate it I use a slightly modified k_progressiveRendering script written by Sylvain Berger. I attached my version if his script.

Works fine on my 2 x gtx470 rig.

Is there any UI for the iray or is everything handled with MEL entries?

[rBrady]

The script that I attached before gives you control over iray with a cute window. It makes iray a check box, there is also min samples, max samples, max time, and error threshold in there too.

[jboris]

Works fine on my 2 x gtx470 rig.

Works on my 1 x gtx470. Iray from MR 3.8 never did work for me (fermi compatibility?), but iray from MR 3.9 works really well.

[Bitter]

(fermi compatibility?)

iRay in 3.9 is now Fermi capable. It wasn’t before.

[d16e45a]

hi , if i active the irradiance particles and i have a crash , i just active in render render settings-options-diagnose bsp- size, i have the bsp2 and the version 64 bits for maya 2011

[Bitter]

You don’t need an indirect lighting method with iRay. It is a path tracer and does that automatically on its own. Turn off FG, GI, IP, etc. It’s unnecessary.

[cgbeige]

too bad there’s no demo of mental ray standalone so I could try this out on OS X. Would have been nice to use as a benchmark for the Quadro 4000 review I’m just finishing up.

[JWRodegher]

Hey cgbeige, please link us to the quadro 4000 review when it’s done, I’m interested to read what another cg guy has to say about it, I actually own one.

Thanks!

[cgbeige]

Well i’m pretty much done with my assessment (I’m reviewing the Mac edition). It’s a huge improvement over the 4800 and the drivers, while still shitty for viewport 1 compared to the Windows drivers, are very good with vp2. It got the same score as the radeon 5870 for a large scene play blast and the msaa doesn’t cause a big hit. There are some bugs and opencl is still AWOL but that’s coming. I like it for sure - two of them with VrayRT would be cheaper than a 5000 and has more cores and it’s great that they didn’t go apeshit with a Mac-specific card (it has a little sticker on it saying Mac version) so the price is the same as the Windows version, which has always been an issue with Mac cards until now. I just hope we don’t have to wait for 10.7 for opencl support (the betas have this but the viewport is unusable in Maya with the 10.7 betas). New GL 3.2 implementation so that’s to be expected.

But I’ll put the link yo the full review in my sig later.

[d16e45a]

You don’t need an indirect lighting method with iRay. It is a path tracer and does that automatically on its own. Turn off FG, GI, IP, etc. It’s unnecessary.

tanks, i dont know

[JWRodegher]

Ok, thanks for the short version. I’ll keep your sig in check for the complete one.

[tostao_wayne]

The script that I attached before gives you control over iray with a cute window. It makes iray a check box, there is also min samples, max samples, max time, and error threshold in there too.

Sorry rBrady, where did you attached the script? i can find it, probably i’m blind

[xtrm3d]

i have questions about some problems ,
got almost everything resolved thanks to the answers in the other thread

i am asking here as this is a more iray centered thread , and that may be more people would chime in with suggestion .

i did install the script : fine
turned off the frame buffer mode : fine

i can now render with iray
the problem is that my ipr crash everytime it try to refresh

3 questions :

• do anyone else have the same issue ? :curious:
• what to do ??
• could it be video drivers related ? :lightbulb

thank you for any light that could be shed into this matter

[LinchpinZA]

Hey xtrm3D

I was testing iray with a work colleague a few weeks ago on maya 2011. Yeah we also experienced those same issues. I guess it stems from iray not being propperly intergrated to maya yet ?
I would like to know if the same crashes happen on 2012.

[rBrady]

Sorry, I forgot to attach my script to this thread.

Its not officially supported at all, so crashes are to be expected. It’s a “use at your own risk” scenario. Try a clean scene with some simple geo first. Its easy to run out of memory and crash the app. Its a bit like going back to the 32bit days.

BTW, I got binary proxies working, they work great. Once I get to 64 trees I run out of memory and it crashes though.

Ryan