Hello to all
I have to make a difficult question.
I am a newbie to V-Ray and I’m trying the free demo of version 3.40 for sketchup.
I’m trying to make a render of a room in my house that I should change the furniture.
I do not understand why the walls take on the color of the floor.
I tried to change both the flooring material of the walls but the result does not change
Can you give me advice on where I’m wrong?
Thanks a lot
Mauro
Hi,Mauro
The reason is explicit
Floor contributes to Global Ilumination
You see something in the real world, let’s say a red flower. You see it is red because it absorb other color of the light and only reflect red color(aka color of itself)
The floor reflect the light,which is the color of itself,as you can see is orange.
Color of the Wall which is nearly 255 255 255（aka white color） and reflect all the color of light it receive
So the wall take on the color of the floor.
There is several way to avoid this situation
You can try out Override Material which will lead you to what you want IMO.
https://docs.chaosgroup.com/display/VRAYSKETCHUP/Override+Material+%7C+MtlOverride
Best regards.
Wow.
Your explanation is better than a scientific documentary.
I have read the help page, and I solved the problem.
However, I find this a strange thing.
The color reflection would have put as an option rather than a default.
But I’m a newbie.
Anyways, this is the new result.
Thanks a lot !!!
Color reflection is something that is always occuring. So this should always be on (I don’t know if it is even possible to turn off). Anyway, you should never use complete white for a material since that doesn’t render well. For white I use a max of 230,230,230. You can always brighten it up in postproduction.
BTW. for a newbie, your renders are already looking good!
Best,
Peter
I second peter’s opinion. 
You can always fix those little things on post.
taking saturation of red value down help to solve that problem. Even in the real world photographers have to deal with white balancing because the light itself and objects do effect light colored surfaces.
I am also curius to ask how you managed to line up the background image outside with beginner’s techniques?
It was the easiest thing.
I created a rectangle, and by the SketchUp texture placement options, I positioned the photo, made through the room window with the celluar with the panorama option.
haha, so it was sort of eyeballed to line up.
What is “celluar with the panorama option”?
Are you refering to cubic panorama?
I’m sorry for my Italian anglicized. 
I took a picture with my smartphone using the Panorama option (merge multiple photos to create a unique photo).
oh I see!
So, no fancy way. But looks great!
I see now that you also got an spherical light in your scene. Have you tried rendering with only the skylight? Maybe use an arealight just outside the window to brighten the interior a bit.
Best,
Peter
I could try, but it would not be very real.
Today expires V-Ray 3.4 demo and rendering … bye bye
So what was a solution anyway? What do You mean by “color reflection”?
Hi Dscitizen,
What I meant was that for instance a red wall will always reflect a little red back to other surfaces. This is how it works in real life. Maybe you can let Vray ignore that but I’m not sure where to turn that down or switch it off.
https://en.wikipedia.org/wiki/Cornell_box
Best,
I was wondering if You are talking about some switch (option) in vray “so this should always be on” and that confused me. But thank You for reply.