Vray Gi results with Mray please help me

[Cesar R]

Hi guys, It seems to me that with vray i can get better results than with MR, however I want to learn mental ray bc it is challenging. Although at this point I am not sure if the extra effort it worth it.

 

I noticed the Vray has an eviroment GI dome, whereas MR and FR do not, so my question is how is this accomplished with theso render engine specially in MR. If you take a look at the attached image you will see render #1 looks very good and all i did was select the vray demo render and enable indirent illumination and enviroment. Then I switched to MR and changed the materials from standard max mat to the architactural mat, and I kept all the setting the same. I engabled GI but I dont seem to get any light or light bouncing. In the GI tab of mental ray I used higher values for the Max depth and max reflections in efforts to make this work, but no change at all. How do you guys get such pretty renders with MR? I need seriousl help. It seems to me the MR is only good for interiors.

 

In the attached images #1 is vray ans #2 is MR.

 

I can also attach the scene for you guys to play and help me.

 

Thank you very much !

[pixelperfectg]

Add a skylight to your MR scene and make the color of it almost white and the renders should look similar. MR uses the skylight as the "environment GI dome"

 

In the past I have also setup a dome around the scene and applied a glow shader for this. I have example scenes on my MR info page if you're interested.

 

http://jeffpatton.net/Max6/index.html

 

(click the image info button to download any of the scenes)

 

Jeff

[Cesar R]

Jeff thanks for your help,

 

so the correct way is to use the sky light and a "sun" spot light.

should i only use the "indirent illumination [GI] when rendering an interior?, I am asking this bc i saw your scene where you use the done and all you have on is FG... ? why is that?

 

Thanks =)

 

I preciate your help very much !

[pixelperfectg]

I have FG enabled because Max's skylight will only work if FG is enabled. For proper photon "bouncing" you'll need to use GI.

 

So for a sunlight outdoor scene I would setup a MR spotlight for the sun (yellowish tint). Enable GI. Insert a skylight and set the color to a blueish tint and turn on FG.

[Cesar R]

ok great,

 

I have made some progress thank to your help,

 

I did the get the secene to work and light up just like the vray scene if not better, and then I took a break to model some realistic stuff just to make it more adequate for this forum.

 

Take look at the Jpeg if you have a chance and help me figure out what is the deal with the light leak at the bottom of the wall where the chairs are against. I have tryed to increase my photons from 3000 to 30K, and I just decreased the FG number to speed up the rendering.

 

My understanding if the following what i comes to FG parameters and please correct me.

 

The more FG samples the more of the slack from the GI that i will be able to pick up, and then when I use a radius, the smaller the radius the better and more defined the FG solution become, meaning I get more shadow definition and geometry details..? or not?

 

I wish the help file would explain this better... (you guys are doing a great job, I just get confused easily ive been researching all day long)

[Cesar R]

here is the same scene so you can compare it to the vray render

[pixelperfectg]

You're getting that gap at the wall because of the shadow map. In MR 3.2 (max6), you couldn't use regular shadow maps on your lights with MR. You had to use either raytrace or MR shadow map. However in Max7 it appears you can. I was able to adjust the shadow map parameters and decrease that gap. But it might be best to just use either the MR shadow map, or raytrace in the future. Probably better still, use the MR lights.

[Cesar R]

you are right, as soon i switched to raytrace, the gap is gone ! and the quality of the render is better too.

[Cesar R]

here is update with some color and materials just as a test.

its true by using the raytraces shadows the image improved much.