Need Darker daylight shadows

[RevitGary]

I am using max 2009 New to Mental Ray. Having many problems.

 

The current one is My shadows are not very dark in my exterior scene.

I have a stucco applied I believe it might be a material problem.

 

Also when you see into the main room the wood ceiling looks like it is lighted.

There are no lights other than sun and sky.

 

any ideas?

[Justin Hunt]

exposure control- darken the shadows and or mid tones

 

What type of material is the stucco? Hopfully an A&D

 

jhv

[RevitGary]

yes it is an AD . I brought the file home. and I am now rendering it and it is very dark inside. The one at work is xrefed from master file. Its a Revit fbx thing. So I think maybe it is getting lights from the xrefed scene even though I did not include lights in the merge.

[Justin Hunt]

when you render , how many lights are listed in the scene stats? if you are just using a daylight system then only 2 lights should be there.

 

Also check that your gamma settings are the same on both machines.

 

The colour calibration could be different on the two monitors as well which could account for the differences.

 

jhv

[RevitGary]

Its not the monitor, its a drastic difference. There are only 2 lights listed. I think it might be GI. Should that be turned off? I am new to this mental ray thing. I am very good with scanline and now I am making the jump to mental ray. So I assume I have some bad habits.

[RevitGary]

its not the monitor. I just but a new light daylight system into the model at work and now it renders black

[Crazy Homeless Guy]

its not the monitor. I just but a new light daylight system into the model at work and now it renders black

 

I think you are assuming when people say your gamma is wrong, you feel they are referring to the gamma of your monitor profile, when they are actually referring to the gamma of your Max settings. Go to Customize > Preferences... > Gamma and LUT. Are the settings the same on both computers when you look at this dialog?

 

Just a guess.

[RevitGary]

I figure out what some of my problems were. I had a sky sphere in my scene from my scanline model a hollwed out sphere with a sky image mapped to it. I forgot it was there I had it displaying as a box. I made all kinds of adjustments to counter it. it was better just to get rid of it and put in a new daylight system. now I am tweaking settings and things are getting better.

[RevitGary]

Ok things are going fine. I decided to see what GI does. It seems to freeze while rendering. the staus bar says it is rendering then just stops. Is GI not a good idea in exterior views?

[Camby1298]

For the most part no. Ya dont need many multiple bounces of light on an exterior scene; most of the objects are within direct light. And FG alone will adjust for any small amount of bouncing. If there isnt enough, you can set your diffuse bounces up a couple (around 2).

 

-A general rule of thumb is: If you need more than 2 diffuse bounces from FG, than you need to initiate GI then (if doing Interiors IMO), and use the photons to bounce light around.

[Crazy Homeless Guy]

GI in terms of Photons are not really needed for exteriors. GI in terms of final gather should be enough. I don't fully understand why MR doesn't refer to FG as GI also. To me it seems like it is.

[Justin Hunt]

Whilst not contradicting what the others have said, here is an argument to use Photons for exteriors

 

You can used Photons for exteriors, although you will get a very different look

 

With FG only the shadows are greatly infuanced by the sky colour, as such are very blue. With Photons and FG the shadows are warmer as the skylight isn't bounced as much.

 

Multiple bounce FG can take longer to calculate, compared to multiple bounced Photons.

 

If you have very deep spaces, photons are able to get light deeper into these spaces. Mainly due to the multiple bounces.

 

By setting the Photon target for the sun, it is possible to get very detailed lighting with relitivly low Photon settings.

 

When using Photons, FG "cleans up" the photon solution so very low FG settings ,like Draft, work well. As such very quick to calculate. Especially as the diffuse bounces are set to 0. Of cause you can use higher settings to get more detail (although diffuse bounces remain at 0), it will take longer to calculate.

 

Here are two renders, 1 is a 3 bounce FG, renders in 6:22 and the other is 30 bounce Photon and FG, renders in 4:19

 

Note the differences is the shadow colour , colour bleed and the light in the deep areas.

 

You decide which you prefer and go with that methode

[Crazy Homeless Guy]

Okay, I'll buy that.

[Justin Hunt]

[RevitGary]

" the other is 30 bounce Photon and FG, renders in 4:19"

 

Where is this 30 bounce photon setting of which you speak?

 

I think I need to bounce photons in my exterior view due to a tunnel condition I have outside. Basically an over hang near a large growth of foliage. I have one specific view looking into this area and it is very dark.

[Justin Hunt]

in the Indirect Illumination panel of the render setup, Global illumination , Trace Depth, the Max Trace Depth is the number of bounces.

 

jhv

[Crazy Homeless Guy]

Whilst not contradicting what the others have said, here is an argument to use Photons for exteriors

 

You can used Photons for exteriors, although you will get a very different look

 

With FG only the shadows are greatly infuanced by the sky colour, as such are very blue. With Photons and FG the shadows are warmer as the skylight isn't bounced as much.

 

Multiple bounce FG can take longer to calculate, compared to multiple bounced Photons.

 

If you have very deep spaces, photons are able to get light deeper into these spaces. Mainly due to the multiple bounces.

 

By setting the Photon target for the sun, it is possible to get very detailed lighting with relitivly low Photon settings.

 

When using Photons, FG "cleans up" the photon solution so very low FG settings ,like Draft, work well. As such very quick to calculate. Especially as the diffuse bounces are set to 0. Of cause you can use higher settings to get more detail (although diffuse bounces remain at 0), it will take longer to calculate.

 

Here are two renders, 1 is a 3 bounce FG, renders in 6:22 and the other is 30 bounce Photon and FG, renders in 4:19

 

Note the differences is the shadow colour , colour bleed and the light in the deep areas.

 

You decide which you prefer and go with that methode

 

Justin,

 

Are you using a sphere around your building to bounce the photons back at the building, or are you simply using the photon target a setting a radius?

 

Also, can you share a basic scene with just a box and sun with photons for me to look at and study? I am currently getting no difference in my lighting when I use sun photons and when I don't use sun photons.

 

Thanks,

Travis

[Justin Hunt]

No I don't use a sphere, just the photon target. If I ever do use a sphere I make sure it doesn't interact with photons of FG. Mainly because the sun is an infinite light. ie light is case from infinity, not just from the suns location. The sun angle is really the only relevant aspect in terms of its location.

 

Sure I'll set something up. I tend to start with the default values. Make sure the photon target is just bigger that the scene or area of focus. Once I am happy with that I increase the diffuse bounces and photons per sample and if nessesary the Average Photons per light,which ranges between 40000 to 800000. Probably the most important setting to get right is the Sample radius, I set it something relevant to the size and detail of the scene.

 

JHV

Edited May 4, 2009 by Justin Hunt

[Crazy Homeless Guy]

No I don't use a sphere, just the photon target. If I ever do use a sphere I make sure it doesn't interact with photons of FG. Mainly because the sun is an infinite light. ie light is case from infinity, not just from the suns location. The sun angle is really the only relevant aspect in terms of its location.

 

Sure I'll set something up. I tend to start with the default values. Make sure the photon target is just bigger that the scene or area of focus. Once I am happy with that I increase the diffuse bounces and photons per sample and if nessesary the Average Photons per light,which ranges between 40000 to 800000. Probably the most important setting to get right is the Sample radius, I set it something relevant to the size and detail of the scene.

 

JHV

 

Thanks. I was using the Manual Setting override in the - mental ray Indirect illumination roll out within the Daylight assembly. If I turn that off, and use the Automatic mode, it works. Maybe I simply didn't have my settings high enough for the Manual mode.

[Justin Hunt]

interesting, manual should work as well. I do prefer to leave the sun's photon set to automatic.

 

If you like you can shoot the scene over to me and I can take a look. Strip it down of cause:)

 

jhv

[salf]

Multiple bounce FG can take longer to calculate, compared to multiple bounced Photons.

 

When using Photons, FG "cleans up" the photon solution so very low FG settings ,like Draft, work well. As such very quick to calculate. Especially as the diffuse bounces are set to 0. Of cause you can use higher settings to get more detail (although diffuse bounces remain at 0), it will take longer to calculate.

 

Here are two renders, 1 is a 3 bounce FG, renders in 6:22 and the other is 30 bounce Photon and FG, renders in 4:19

 

 

And all this time I thought adding GI to FG would only increase my render times (since I get nice results with FG only), when it could actually be the other way around.......gonna start using FG + GI and see.....