3dsmax grainy render using mental ray daylight system

[fionamcclay]

Hi,

 

 

I'm experiencing issues with grainy renders using 3dsmax and was wondering why this might be. I'm using a daylight system and have tried changing FG bounce to 6, increasing the min image precision to 4. I was wondering if anyone had any suggestions as to why th eimages are coming out grainy?

[Francisco Penaloza]

Hi,

What version of Max are you using?

Those black/white irregularities are actually not noise, that's lack of GI samples. You can use different approach in this situation.

First place a skyportal right above the ceiling opening. this will help your exterior lighting to get inside with more energy.

Second, you try to use GI (photon mapping) that will help FG to illuminate your scene.

Third option if you only want to use FG, you not only need to increase the bounces of Final gather, you also need to adjust Initial point of density, Rays per point and interpolation.

so for instance, I can guess you could use Initial point of density at 0.8 Rays per FG =150 and interpolation = 90

This will produce a longer render time any ways, so you need to check what works better for you trading quality Vs speed.

 

Using Photon mapping will give you faster renderings. It will make your image a little more orange/yellow but you can compensate with color balance in the exposure controls.

 

hope this help you, let us know.

[fionamcclay]

Hi,

 

I'm using the 3dsmax design 2016

 

I tried the skyportal and using GI but was still experiencing the black/white spots

 

In the end changing the Initial point of density to 0.8, the rays per FG to 150 and interpolation to 90 as you suggested seemed to do the trick.

 

Thanks for the tip, great help and has improved my images significantly!

[Francisco Penaloza]

No problem, glade to help, but remember this are not magic numbers, each scene will need different values, take a quick read to Mental Ray manual and learn what each of these values control so in your next project you know where to go and adjust what is need it.

 

Best luck.