Render times?

[RevitGary]

I am slowly getting my head around all this mental ray stuff.

I realized I was not shooting nearly enough photons in my scene.

 

So now I have a large apartment model with a MR sun and sky and 7 sky portals. Note there are two layers of pro materials glazing at each window. One for the windows one for swinging glass doors in front of the windows. I dont know if this matters or if photons pass thru both with no problem.

 

The average GI photons in the render set up are set at 10,000 the photons per sample are set at 800.

 

In the sun multiplier I have energy set to 3 and GI photons at 50.

 

For the sky portals I have the multipliers energy set to 2 and GI photons at 10.

 

This gives me a reasonable coverage of photons in the interior. I currently have no interior lights.

 

This gives my nice rendering but now my rendering times are 1 1/2 hours at 1/4 - 4 aa on a really kick butt machine.

 

What are the things I should look at to get me better render times without much loss of quality? Plus I plan on cranking up the aa for the finals so it will probably double the times.

 

Thanks!! as always

[Tommy Burns]

I would try it with just one sky portal stretching across all the windows and maybe calculate photon map and fg map with your glass turn off. Then use the saved maps and turn back on the glass and render it should be a lot quicker. I also wouldn't change the portal settings just change the F stop (exposure settings to brighten it up). Make sure you are using mr preset of interior

Hope this helps

 

Tommy

[RevitGary]

The building sticks out at the corner window bays that is why I didnt use 3 one for each side. I have 2 on each corner and long ones spanning several window bays on each side. I thought it was best to keep the portals as close to the windows as possible.

 

I have 30 renderings. I have calculated my photon map with the windows turned on and a grey material overide for testing. Would I need to generate a photon map for each view?

Edited December 5, 2009 by RevitGary

[Justin Hunt]

IF nothing changes other than the camera location then you can re-use the photons map. Photons are not view dependent. The Final Gather however is view dependent. So incrementally add the FG for each view, freeze the solution and re-render. DO the calculations at a lower resolution than the final which will help speed up the calculations a tad.

 

jhv

[Crazy Homeless Guy]

I have ran into a lot of problems with MR Sky Portals. They are slow, and lack a lot of control. Tom is right, those are more than likely what is causing your slow render times. If there is anyway to do away with them, and get enough light into the scene otherwise, I would do that.

[thorsten hartmann]

Hi

 

the Portal Light from mental ray are very fast, but the Autodesk Developer Team are very bad and have not include important optimizing Functions. You must use the original Shader and put them in to the Light Shader of your Portal Light.

 

The shader then blocks FG rays and replaces them with direct light of high quality with the same intensity and color. Also emits photons in a similar way.

 

- cutoff_threshold: You can optimize the Angel of emmiting from the Light

 

- shadow_ray_extension: You can optimize The Shadow from Outdoor or Indoor (to eleminate the Shadow of a Window Frames, set the Value to negativ value in Units: for Example 0.3m and the Window Frames create no Shadow from the Protal Light, that bring speed and Quality. If a Tree Outdoor ( 30 Meter distance of the Window) and you want that the Portal Light create a Shadow from the Tree in the Room, set the Value to positiv value, for Example 30 Meter.

 

- emit_direct_photons: You can optimize the Shadow to FG-Ray or Photon Map (very fast)

Edited December 6, 2009 by thorsten hartmann

[Crazy Homeless Guy]

Hi

 

the Portal Light from mental ray are very fast, but the Autodesk Developer Team are very bad and have not include important optimizing Functions. You must use the original Shader and put them in to the Light Shader of your Portal Light.

 

This kind of stuff really frustrates me, and more and more it makes me have to switch back to Vray for certain project.

 

Autodesk is trying to simplify the interface of MR too much so that it is easy for everyone to use. At least that is what I think is happening. They should really consider implementing an advanced MR interface profile, and a simplified interface profile.

 

The one they have now would be the simplified, and the advanced one would have the features that MR has implemented so that the advanced user could really take advantage of them.

 

I disagree that the portals are fast. They have added quite a bit of rendering time to several of my projects. I had a post on Mental Images where I was wishing for an option that allowed for interpolation on sky portal samples. I still think that would be a good idea, even though others did not agree. Though it would only really be feasible for stills. Or at least I think it would only be feasible for stills.

 

The samples off the sky portals do not appear to be smoothed much at all. Unless the sampels are set to 16 or better, they are visible in my scene. Set the samples to 4, and you can see the individual specks.

 

I guess an alternate would be to have the sampels smoothed as part of the FG interpolation. Maybe it is to early, and my mind is not processing things correctly, but it seems like that might be a solution.

 

But anyway, ....please Autodesk, make an advanced profile for mental ray in 3dsMax.

Edited December 6, 2009 by Crazy Homeless Guy

[RevitGary]

Thorston,

 

Its always something... I dont even know what you are saying.

My sky portals dont have the options you are showing.

 

How do I get the "mental ray light shader" options in my sky portal settings.

I dont even see the "architectural:environment portal" light shader option in my material browser.

 

my attachment shows my settings next to your settings

Edited December 6, 2009 by RevitGary

[Crazy Homeless Guy]

You need to un-hide a few options.

 

for 2008 and 2009...

http://mentalraytips.blogspot.com/2007/10/production-shaders-hidden-treasures-of.html

 

for 2010....

http://forums.cgsociety.org/showthread.php?f=6&t=754187

[Justin Hunt]

even adding a blackbody shader to the portals makes them much faster and cleaner.

 

If you dont want to use portal lights, then make sure the suns photon emiter radius fits just within the window openings. to be sure as many photons from the sun enter the room

 

jhv

[RevitGary]

I have the sun photon radius limited to my window size.

Ill try and figure out the shader thing.

any other comments on my settings? Changing the energy and multiplier is something new to me. Are those setting looking ok?

[Justin Hunt]

I tend to leave the sun and sky and portal lights energy levels @ 1 and have the exposure control Physical scale set to real world (ie not unitless).

 

If I have photometric lights as well, then I increase the photometric lights energy up. This way I can have the lights multipliers at what they should be and still be able to see them in the render. To get the energy value I divide 80 000 by the lights intensity. usually comes in around 20 to 30.

 

If this is the right way of doing it I cant say, it works for me.

 

jhv

[RevitGary]

I am familiar with the unitless vs physical units in the exposure control. I think I read one of the developers stating he thought making physical units the default was a mistake. So I have been using the unitless options. Not sure why, its just something I read and chose to go that route.

Edited December 7, 2009 by RevitGary

[Justin Hunt]

If it works for you great carry on. I suppose the only difference is to get the photometric lights energy level divide your physical scale by the lights intensity.

 

jhv

[RevitGary]

I am trying to figure out this unlock shader thing I did what is described in a post from the other site

---------------------------------------------------------------------------

"The Light Utilities section of your 2010 base.mi file should look like this:

 

#-------------------------------------------- Light utils

 

declare shader

color "mib_cie_d" (

scalar "temperature",

scalar "intensity"

)

version 1

apply light, texture

end declare

 

declare shader

color "mib_blackbody" (

scalar "temperature",

scalar "intensity"

)

version 1

apply light, texture

end declare

 

#-------------------------------------------- Shadow

 

Then, in order for it to appear in 3dsmax 2010 you now need to open the base_max.mi file and that’s where you’ll actually unhide the cie_d & blackbody shaders. In the base_max.mi file scroll down to the GUI sections for both the cie_d & blackbody shaders and put a # in front of the word hidden. Should look like this when you’re done:

 

gui "gui_mib_cie_d" {

control "Global" "Global" (

# "hidden"

)

}

 

gui "gui_mib_blackbody" {

control "Global" "Global" (

# "hidden"

)

}

 

After doing that, you’ll find it’s available for use in 2010."

--------------------------------------------------------------------

 

I still dont see the additional options as shown by thorsten.

I dont know how I should be applying these options to the skyportals.

 

I have looked everywhere in the material browser and dont see anything about an "architectural:environmental portal" shader

 

I also dont see the "mental ray light shader" options in the skyportal settings list under the mental ray indirect illumination options.

I do see the blackbody and cie_d options in the material browser although i have no idea what to do with them.

 

help!

 

thanks!

[thorsten hartmann]

hi

 

you see only the light Shader option after create a light. You must go to the modifier. And second you must set the custom GUI Switch to "3ds + mental ray", not the option "viz+mental ray".

 

The Shader to unhidden find you in architectural_max.mi.

 

   gui "gui_mia_portal_light" {
      control "Global"  "Global" (
          "uiName"      "Architectural: Environment Portal",
          "category"    "Light",
         # "hidden"
      )
   }

 

mfg

hot chip

[Justin Hunt]

I gave this on a try on my last project and it works a treat. Much smoother than normal portal lights and quicker too.

 

jhv

[RevitGary]

I am in the middle of a try myself. Stay posted I am sure i will have more questions.

 

do I need to redo my photon map?

[RevitGary]

Wow I just did my first test. A rendering that previously took an hour and a half took 12 minutes. wow still testing to see if im doing things correct

[RevitGary]

Ok now I see why it was so fast. No photons. see attachment. Anyone know why I am not getting any photons?

[RevitGary]

ok some help here would be greatly appreciated ... as always.

See attached 2 images. One is with no mental ray light shaders enabled in the sky portal settings. Looks pretty good this is what I have been rendering with.

 

The second image The only difference I turned on the enable setting in the mental ray light shader and have the architectural:environment portal in the light shader and photon emmiter shader.

 

If you notice my previous post I dont seem to be getting any photons from this..

 

Help!

Thanks!

[thorsten hartmann]

hi

 

the 3dsmax portal_light, can only FG-Rays as a Raytrace Light. The original Light Shader can FG-Rays or Photon emmiting, not both at the same time.

 

- When you use FG-Rays, set FG-Rays emmit to "on" and Photon emmiting "0ff" (Result is very good detail Shadow and slow)

 

- When you use Photon, set Photon Emmiting on and "FG-Rays" emmiting to "off" (Result is very smooth Shadows and fast)

 

- Why have Reverse ="on"? That lets emmit the Light in the other direction.

 

NOT -> FG-Ray + Photon = "on", that don´t work

 

mfg

hot chip

Edited December 21, 2009 by thorsten hartmann

[RevitGary]

Thanks again thorsten I am looking into this.

 

When you say you should not use final gather and photons at the same time you are referring to the settings within the environmental portal parameters correct?

 

or do you have to turn off final gather in the indirect illumination setting also?

 

Where did you come up with all of this? I have looked around and cannot find any documantion on all these MR environmental shader settings.

 

Thanks again

[thorsten hartmann]

hi

 

When you say you should not use final gather and photons at the same time you are referring to the settings within the environmental portal parameters correct?

 

Yes that is what i mean, the environment portal parameters.

 

in your 3dsmax/help/ directory is a pdf file "mr.architectural.shaders.pdf". Look in this file and search the word "mia portal light".

 

ps: set the transpareny color to white.

 

mfg

hot chip

Edited December 21, 2009 by thorsten hartmann

[RevitGary]

Here are 2 tests. The first is the old photons the way I have been working.

the second is the new photon settings.

 

They arent even close the new settings arent putting nearly enough light into the room. What am I doing wrong?