Flat environment - refraction problem


#1

hi all,

Anyone could tell me why can I see the whole column in my picture, as behind the glass there were nothing except background? Upper part of the column should not be visible, because there is a ceiling inbetween the glass and background picture, what’s wrong here?

How to achieve proper refraction here leaving the flat background how it is ?

thanks


#2

Its kind of hard to give you a definitive answer by your explanation of the scene but here we go.

The upper part of the column being visable may be due to viewport clipping if the image is a grab of the veiw port or if not it could be the camera far clipping plane.

The reflection I don’t know as I have no idea what you mean by flat background. If you mean you have a image that is screen mapped in your environment then any reflective materials will seem transparent and reflections will not look right. To get around this if using mental ray you need to use a environment/ background switcher with your screen mapped image in the background slot and a copy of that image with spherical mapping in the relection slot.


#3

Yes, I have screen mapped environment.
The reflection/refraction is not right, but using spherical map does not solve the problem.
I want this image in the background to be rendered together with my scene, so that it’s properly visible through the glass as well.

To be more precise - when You look at the picture, the upper column reflection is not reflection, but it’s like a refraction. And the refraction shouldn’t be there, cause behind the column there is a roof, and just behind that there is a background, not before. I hope I’m clear now.

What should I do then ? I could create a plane in front of the camera and behind my object, have it mapped but each camera move would change the composition and my object placement in the scene then.

So isn’t there any way to have a flat image in the environment so that it would be properly refracted through glass and wouldn’t be stupidly flat-reflected at the same time where it shouldn’t be?


#4

Well in that case you should do as I said in the previous post and use a environment/ background switcher with your screen mapped image in the background slot and a copy of that image with spherical mapping in the relection slot.


#5

johny, I’m not quite sure what You mean by ‘environment switcher’.
I work on Vray, if it changes anything.

I tried to put same map into the reflection slot in vray rollout but it didn’t do the trick.
It looked like environment map in 3ds MAX were ‘more important’ for the reflection than the one put into the ‘reflection’ slot.


#6

The environment/ background switcher is part of the shader network in Mental Ray. It allows you to use one image for the environment and another one for reflections.

Since you are using vray you would think that the reflections overide would work but don’t use the same shader you have in the environment. Make another one with the same image but with spherical mapping.


#7

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