Falloff?

[marksee]

I am working on the attached project. I don't understand how the ceiling is always a problem in all of my renders. The lay - in act ceiling turns the floor color in almost every instance... Adjusting the falloff never seems to matter. Is this a color bleed issue? Nothing else seems to be effected except for the ceiling. All materials are arc & design materials. In one instance, I changed the floor to white, saved the final gather solution and reused it with the tile material and it worked. Problem comes in to play when I move to a different camera view. I don't want to render each image twice as they take over 2.5 hours per frame!!! Please Help!!!

[Tommy L]

http://www.cgarchitect.com/vb/25127-problems-black-floor-rendering-vray-urgent.html

 

The link is for a similar problem. May help, but its different software.

[Justin Hunt]

As well as the FG settings.

 

A tip to speed up FG rendering is the set the FG to read/write. The image resolution to at most half the final resolution and the image sampling to 1/64,1/64.

 

Once the FG is completed , Freeze the FG, set the image resolution to full and image sampling to 1,16 (or what ever you need)

 

Two killers for rendertime are 1, do a high resolution FG with excessivly high settings and two glossy reflections without useing Fast interpolate.

 

To help control the colour bleed, play with the diffuse level settings.

 

JHV

[marksee]

Thanks for all the comments. I will post some more detailed info re: the rendering settings. The A&D shader I left pretty well alone. The diffuse map has the jpg I made for the tile, and the b&w bump map - matching the diffuse grout lines. I tried playing with the photon slot under mental ray connect - with the photon basic (base) shader - and changing the diffuse/specular to grey tones - all the way to white - and it hasn't helped at all. I am fairly new to mental ray - and its been a long project because of it. It seems that I am almost there but I gotta get this project done in the mean time. It used to be easy w/ radiosity just using the advanced lighting override. But no doubt - the quality of mr is much nicer.

 

also, w/ the final gather and gi solution - is this a global solution, i.e. everything not visable to the camera being calculated? This approach did work, making the floor white and saving the solution - but one I switched camera views weird shadows found their way on to the ceiling that weren't there when calculating fg and gi outright.

[Justin Hunt]

Photons are global but Fg is view dependant. You can save the FG from different cameras to the same FGM.

 

A&D shaders dont need the Potons shaders, they are built in.

 

JHV

[marksee]

Ok, well I suppose I should shift my attention to other places. After reading a plethora of tutorials, forum articles and conversations, I haven't really found a "real" solution. The popular consensus (seemingly) is the go with the white floor w/ a saved fg solution, however, this would mean that I would render all my frames w/ a white floor first - saving the solution - and using that solution w/ the real floor map? It just seems like not the "right" answer - and at such high render times a little excessive - especially with 4-5 camera views? Seems like there should be a way to manually set the floor to "glow" white as photons react with the floor instead of the brown color that is bleeding to deep into the image. I must be missing something.......

[Justin Hunt]

If you are using Max9 than make your life simple and only use FG, no Photons.

 

Take some time to run through the tutorial on rendering interiors with MR that ships with Max. It will give you a good start to rendering with FG.

 

JHV

[Ravendark]

I have a tutorial from a magazine here, to reduce the effect the floor has on the GI of the scene it recommends this...

 

Add a Photon Basic shader in the mental ray connection rollout at the bottom of the floor material.

 

Set the Diffuse colour of this shader to 50% grey and change the spec' colour to black.

 

It says that the colour you have added here will tint the photons.

 

Delete photon map and re-render.

 

I reckon you should do this for your walls also (presuming it works).

 

Hope this helps