MR Family Room - Render Setting Help?

[MegaPixel]

I purchased the "Starting with Mental Ray" pdf available through the VM Store and found it very useful in learning MR terminolgy and proper uses of shaders and the like. It was however, fairly lacking with respect to rendering quality and rendering workflows which is why I am here.

 

As you can see from the image below, I still suffer from the classic "Splotchy" syndrome even after turning up what I thought were decent FG settings. I'm also trying to figure out why even though I'm saving my Photon and FG maps and reusing them, the renderer still chooses to reprocess these areas?

 

I think it's time for me to figure out how to use the FG max and min radius values instead of leaving them default. I used to leave my Photon sampling value default also but found I got better results manually adjustign it's size. The overall size of the goemtry in this scene is 57' x 37' (there is alot more behind the camera). Can I use this info. for determining the FG radius values or is that just for Photon size?

 

Anyhow, I posted my settings below also. I'd appreciate any comments or crits to help me improve my workflow in thew future. Thanks guys - Mega

[Hao La]

Please post your lights settings, it's all about lights, use manual setting for light instead of adjust photon in render setting tabs.

_The contrast (44) is too low , FG 1000 is too high for me.

_GI Radius (72") doesn't make much details on shadow (leave this default value)

_FG Radius : using small value will get more details on shadows but longer render time.

_How about Trace Depth in FG option ? how many bounces ?

_Sampling quality :

+Box: Simple mathematical average of the samples. This is the fastest and most blurry filter, so fine detail is lost.

+Triangle: Sharper than Box, but slower. Samples farther from the center have less effect on the pixel.

+Gauss: Soft image, intermediate quality and speed.

+Lanczos: Pretty slow filter, but the result is very sharp.

+Mitchell: The most precise but slowest filter. This is the closest to the perfect, ideal filter: it filters without blurring.

[MegaPixel]

I'm sorry, I knew I was forgetting something. I attached my light settings screenshot. Amazingly enough, I'm only using 1 Daylight system in this scene.

 

As for the FG radius, I've left it default which I think is 1 inch? If going lower means better results, then should I try 1/2 inch? 1/4 inch? or should I work with pixels?

 

I havn't played with Trace depth or bounce on FG - any suggestions on what to shoot for?

 

Thanks - Dave

[Hao La]

Oh ,ok, you used daylight system. In my opinion , daylight system does not wrok well with mental ray.

_Using MR Spot Light woth high energy for sunlight instead (less photon than daylight system).

_Using photometric Area light at every opening windows to get diffuse light (this step looks like what you did in Vray. Again , playing with 'manual setting' for each light to get a good result.

_FG Trade depth : increasing the bounces to get more bighter lightning, (you can make the scene brighter by increase the Decay too).

[MegaPixel]

I'm using MAX 8 with MR 3.4 which is supposed to support IES lights, including the Daylight System which renders without having to use final gather - as opposed to the Skylight which does require FG.

 

I also attached the Kitchen Shot which is right behind camera in the first shot above (To give you an idea of the scale of the scene).

 

I didn't want to use multiple lights at every window for simplicities sake and accuracies sake but if you think it will make all the difference?

[auvn]

1. sampling quality 64 is too high (often 16 is enough)

 

2. number of photons is quite reasonable. your photon radius is too large so it make the image looks muddy. (you can reduce photon size, however, should take care whether photons overlap enought to avoid black and bright spot, and increase reflect of photon)

3. your final gather number is too high. I am not good at control final gather radius so can't say much. however with this small sence, you can use final gather radius to increase level of detail at corner of images (probably 12")

4. how your setting for exposure control.

 

AUVN

 

to Hao La: daylight system works fine with mental ray althought it is a little more difficult to control.

reduce decay level can brightern the sence but also make the sence flatter, espcially for photometric light

[Hao La]

AUVN : off course we know when to stop . Daylight system create a real physical sunlight which has huge energy and photon, therefore not only slower render time , but also hard to control the intensity. Using spot light+ sky light is a way to 'FAKE' the daylight system because it is easy to control the energy and photon.

 

Dave : the other things that is very important when working with mental ray are materials. It affects the illumination a lot (at Vizdepot.com , we have experimented about it many times)

 

Lightning test with Mental ray

 

_About FG Radius : increasing the radius will get the render faster, but lack of shadow details. My suggestion is put it at default value

_When using mental ray , Light's type and materials are the most important, the set up is just a final touch.

[carlosjhb]

hello, hola como estan,

[MegaPixel]

I was wondering why I had to drop my RGB output levels by half on almost all of my bitmaps - because there is too much energy from the Daylight System or is it the IES SUN/SKY specifically? Can I still use the Daylight System and switch the IES Sun to a Spot and the IES Sky to a Skylight?

 

Auvn, when you say my FG number is too high, do you mean radius or samples? I left the radius at default - should the radius be around 12" you say and maybe the samples back to about 500 or so?

[William Alexander]

Daylight system for interior lighting is a tough way to go. Using the spots or area lights is a very good alternative at the windows.

 

The 'circles' (lightness channel, LAB mode in PS) shows these artifacts. It could be a number of things.....

*Your scene is not to scale (72" photon setting), which I doubt

*The default FG radius max and min is 1/10nth of the scene extents Max radius and 1/10th of the Max radius for the Min radius.....which means those circles are caused by the min radius being tooo large. If you set the Max to about 12-24" and leave the min you should get better results....1000 samples may or may not be enough for your scene.

*Your total photon count may still be low for any sunlight entering the room from outside. Increasing the count will more evenly distribute the light energy over more photons. That's the problem with the daylight system it has to shoot very large numbers of photons to get an even coverage inside a structure

 

WDA

[William Alexander]

I was wondering why I had to drop my RGB output levels by half on almost all of my bitmaps

 

Are you using exposure controls? They behave in a manner similar to levels and more closely to curves in PS, which can ramp the saturation levels up...Just a thought

 

WDA

[MegaPixel]

Yes, my original settings posted in the first thread show I am using Logo. Exp. Control. This scene is inteneded for animation when complete and I thought Logo. would be a good choice for that? Thank you so much for your input on the previous post. Let me first try to salvage this scene keepign the Daylight system. I went through soo much trouble setting up everything up just right to work with it. I'll make all of your adjustments as suggested and let you know how it turns out.

[auvn]

to MegaPixel: I mean number of sample 1000 is too high for this sence

 

: totally agree that it is much easier and often faster to use standard light than using daylight system

 

number of final gather also depend on setting of photons also