VRay-like interior renders with mental ray???

[Snowcat]

oh! nice work. cool render time:)

visua
show adjustment mia_photographic_exposure and fg

[MAV4d]

Thanx, nothing fancy really:
Physical sun & sky with portals at the windows, FG only, 2 diffuse bounces,
extremly low settings for the fg something like 20 rays if I recall correctly. The portals
did such a good job on the shadows so I didn’t really need much detail from the fg-calculation.

All mia_materials, mia_photographic_exposure with altered white-point.

Cheers

//NIC

could u direct me to the diffuse bounces options for FG?

[Sybexmed]

Hey, what exactly are portals? Very nice render.

Thanx, nothing fancy really:
Physical sun & sky with portals at the windows, FG only, 2 diffuse bounces,
extremly low settings for the fg something like 20 rays if I recall correctly. The portals
did such a good job on the shadows so I didn’t really need much detail from the fg-calculation.

All mia_materials, mia_photographic_exposure with altered white-point.

Cheers

//NIC

[Goksimaster]

Great stuff …

Thise are some of my tests wih sun/sky and portal.

This is a raw render

This one is a little bit tweaked in -ps, and I added subtle DOF using simple ramp
btw the model is a free semple from evermotion…

[visua]

I just had to give the 'ol classrom a go, not superclean but I went for speed rather than perfection, rendertime 2 m 27 s:

[Sybexmed]

I just had to give the 'ol classrom a go, not superclean but I went for speed rather than perfection, rendertime 2 m 27 s:

what are your settings?

[visua]

I just had to push it a little further

[aenrii]

YOU were 100% right.
The problem was a bad setup, mixing portal lights with sky in a wrong way.
Here’s the evidence.

    [img]http://img228.imageshack.us/my.php?image=test06dt3.jpg%5D%5BIMG%5Dhttp://img228.imageshack.us/img228/3924/test06dt3.th.jpg[/img][img]http://img228.imageshack.us/my.php?image=test06dt3.jpg%5D%5BIMG%5Dhttp://img228.imageshack.us/img228/3924/test06dt3.th.jpg[/img][img]http://img228.imageshack.us/my.php?image=test06dt3.jpg%5D%5BIMG%5Dhttp://img228.imageshack.us/img228/3924/test06dt3.th.jpg%5B/IMG%5D[/img][img]http://img228.imageshack.us/img228/3924/test06dt3.jpg[/img]
  
    Many many thanks to everybody.
    
    Lluis

Running into the exact same issues you had. What did you do? Please break it down.
Did you disconnect the shadow-connection in the shadergroup for opaque materials or did you modify the area light shape connections?

I’m confused as hell right now.

In my scene I have mr area lights, with portals (both light and photon shader connections) that use the sun/sky light. The issue with white artifacts on the floor occur as soon as I crank up the area light samples past [high 8 / high limit 1 / low 1].

Wierd things going on…

[Goksimaster]

I just have to ask. Is this an mr sun/sky with portal light because I experienced very very week shadows. Your’s are very strong and I am wondering what is going on , did anyone have the same problem and is ther a solution.
In my scen I have a wide portal light
Use light shape and Visible is one , max samples are at 128. And I conected a portal light to the light shader, Also I am using mia_physicalsky as an environment for the portal light and I use it in mia_exposure_photographic to control the whitepoint.

Look at the shadows coming from the legs of the table

Oh and one more thing I am using GI , and emitting photons from the area light. In the manual they say to also connect the portal light as a photon emitter but when I do nothing happens, photons are not emitted?

[Cuni]

Running into the exact same issues you had. What did you do? Please break it down.
Did you disconnect the shadow-connection in the shadergroup for opaque materials or did you modify the area light shape connections?

I'm confused as hell right now.

In my scene I have mr area lights, with portals (both light and photon shader connections) that use the sun/sky light. The issue with white artifacts on the floor occur as soon as I crank up the area light samples past [high 8 / high limit 1 / low 1].

Wierd things going on...

It’s all about the shader. Just break the connection and everything will be fine.
The more quality you have in your shadows, the higher the artifacts, but it’s all in the shadinggroup connection.
Area lights don’t produce these artifacts, just noise (with low samples).

Hope this helps.

Lluis

[tuddel]

hi guys.i wanted to ask.how did you fix the scale in your model.i think it should be based on world scale?thanks!!

[tinitus]

Also, you have the “finalgather force” mode, which is non-interpolated FG, which practially is very similar to path tracing. In Maya you can enable it with a string option:

"finalgather mode" "force"

/Z

sounds nice! but could you explain how to enable the finalgather force mode?
cant find it in the hidden mr settings and I dont know how to enable it with a string option!
thx

[Jozvex]

Hi tinitus,

1. Open the Outliner
2. Right click in it and turn off ‘Show DAG objects only’ to reveal all the hidden nodes.
3. Find and select the miDefaultOptions node.
4. Open the Attribute Editor if it wasn’t already and scroll down to the ‘Extra Attributes’ section.
5. Expand it, then expand the ‘String Options’ area.
6. Just type over the top of the ‘rast motion factor’ option (the ‘Add New Item’ button is odd… it worked for me once and now it seems to add locked items?)

Name: finalgather mode
Value: force
Type: string

Just hit enter and it should work! This is in Maya 2008 (SP1 actually) for me. Then you can just use the ‘Accuracy’ and ‘Point Density’ settings in the Render Settings to control the quality.

[tinitus]

thx a lot jozvex

[Jozvex]

No problem!

Now I have a question too! How is everyone using the ‘Cm 2 Factor’ attribute on the mia_exposure_photographic shader? I just randomly drag the slider until I can see my scene and it feels like I should be doing something more… proper, with it?

EDIT: Oh I found the answer posted by Djx in another thread:

“I wont attempt to explain all the physically correct stuff, but will offer this suggestion.
In the mia_physicalsky, set the rgbUnitConversion to 0.318, 0.318, 0.318 (this magic number is mentioned in the manual somewhere).
In the mia_exposure_photographic set the cm2factor to 1
Now the iso and fstop will work more a film camera and you can use more meaningful numbers like iso=100, fstop=16 and expect reasonable exposure. Obviously you will need to tweek.”

Yay!

[tinitus]

haha.same with me.
thx for sharing!

[aenrii]

It’s all about the shader. Just break the connection and everything will be fine.
The more quality you have in your shadows, the higher the artifacts, but it’s all in the shadinggroup connection.
Area lights don’t produce these artifacts, just noise (with low samples).

Hope this helps.

Lluis

Thanks a lot man! Working like a charm now. Got the rendertimes down from 23hrs to >25mins, it’s amazing how scalable mental ray is. No wonder it’s more or less industry-standard in film and post…

However, I’m now experiencing spot-clutter artifacts in reflections in a bathroom part of a scene, where a metallic material is reflected. Truly a pain in the a**. tweaking the samples in the materials doesn’t do much else but cost lots of render time.
Boosting up the samples in the area-light in that room helped a little bit, but also seems a bit costly on time.
Also, cranking up the AA-samples to adaptive 2/4 boost render-times by at least 10 - 20 times 0/2 (1/3 looks the same as 0/2), wich looks just as good except for the reflections I mention…

Any ideas about this, anyone?

Thanks! / Anders

[tuddel]

hi all.i had a newbie question again :wavey:
i downloaded the classroom and the bathroom scene.but all i get is black.could it be because my scale is set to centimeter?thanks!

[yoonjin]

Jozvex.

Do you or anyone else have any idea how to control the cm2 for scenes that are not using physical sky, i.e. IBL with FG.

Could one say that cm2 is the same as luminance exposure/area?

[yassein]

hi all
here is my test