How would you do this? #1 & #2

[TomasEsperanza]

Hi,

 

I recently found myself puzzling over this scenario. I achieved a workaround but wondered if: a) the proposed was possible and b) what would be the process you CGArchitects would use?

 

 

In 3ds Max with V-Ray:

 

1) You have a bathroom with a mirror on the far wall, and

a camera outside of the bathroom (pointing towards the mirror).

The camera is to look through the wall/s into the room.

The mirror is to reflect the interior of the room.

 

How would you do this? #1

 

 

2) There is a Domelight (using an HDRI) illuminating the scene outside of the room.

To bring more of this light into the room, through two adjacent walls of the four, you wish to allow the light to pass through the walls but for reflections in the room to be of the interior only.

 

How would you do this? #2

 

 

I would be interested to read how people here would technically address this problem. I know this scenario is not realistic (in so much as light doesn't pass through typical walls), and that an inevitable response is to just allow the light through fenestrations. However, I found this an interesting dilemma to be presented with. Thank you for your responses

Edited February 4, 2015 by TomasEsperanza

[siddharthkolte]

There are two ways you could approach this issue.

 

1. Make the wall not visible to camera but keep it on for reflections and refractions, that way you will get the proper reflections of the bathroom in the mirror.

 

2. Make two separate renders, one from the render camera keeping the mirror black and the walls hidden and the other one as if you are looking from mirror towards the other camera with the walls unhidden. Then composite the mirror render into the black glass and voila you have the interior of the bathroom in the mirror.

 

You want the HDRI that is outside the bathroom to affect the bathroom then basically, you need to keep the bathroom door open or some way for the light to naturally come in. If you are taking the photo(render) from the door side to the interior just fake it by placing an invisible plane light behind the camera and adjust the color to simulate as if light is coming from the doorway. Another idea to bring the overall light inside the room you could place a diffuse only spherical light in the middle of the bathroom or if sunlight, place the spherical light just above/side of the place the sunlight has hit inside the room.

[Amen]

1. Turn on camera clipping in the Vray Camera.

 

2. I would not fake the light coming from the outside. Get a correct exposure using your camera. Use the light sources which are in the bathroom, maybe open the bathroom door and put a vray plane light there.

 

The exterior will look very bright, but that would be similar to a real photograph.

[beestee]

#1 - I agree with Jan K. Clipping is simplest.

 

#2 - There is an option for "cast shadows" or similar in the object properties and "visible to GI" in vray object properties. I used to use these for decals to make it appear that an object was on a surface even when it was slightly offset. I don't believe it is the best solution for your scenario, but it will accomplish precisely what you have asked.

Edited February 4, 2015 by beestee

[Francisco Penaloza]

Yes to use camera clipping, I have done it several time, it works just fine.

 

For the second question, Why would you use a dome light, to illuminate a space that won't receive exterior lighting?

if your space is small and enclose you'll have enough light bouncing to get color variations, just model everything in there and use only the light that suppose to be there, then play with the exposure and you'll be fine.

If you save a exr at 32bit you can bright your scene even more if it is need it in post.

Here is a sample of a pretty similar situation.

[Nic H]

1. camera clipping

2. fix your lighting - its not necessary to do what you are suggesting

[Crazy Homeless Guy]

2. fix your lighting - its not necessary to do what you are suggesting

 

This and all others who said the same.

[siddharthkolte]

1. Turn on camera clipping in the Vray Camera.

 

Wow that is a good option I looked into this... I never knew about the Camera Clipping option in Vray Camera.

[TomasEsperanza]

Wow that is a good option I looked into this... I never knew about the Camera Clipping option in Vray Camera.

 

#1: Doh.. I've actually used this before and had totally overlooked it. I feel silly now... Oh well, at least I've been put back on track

 

Regarding #2: I did go the realistic lighting route, but while working on the scene it just got me wondering... (as one of the benefits of CG is we can escape the constraints of reality to our own ends, whatever they may be)... can we make light pass through objects without making them transparent? So this was more a hypothetical question, in order to broaden ones palette of tricks.

 

Thanks guys.

[Amen]

You could make the wall transparent to the light... but all your refelctions and speculars would be wrong and too big.

[TomasEsperanza]

You could make the wall transparent to the light... but all your refelctions and speculars would be wrong and too big.

 

Yes it certainly seems that way, guess I was barking up the wrong tree

[siddharthkolte]

Being CG artist is all about how we use these powers to our advantage, not as we can do it we must use it.

 

So if you have a lighting effect in mind that could improve the realism in the scene or give a desired effect for the final composition. Then go ahead and fake lighting coming through the walls, or even place invisible lights within the scene to get the desired effect. You could also do these changes in post depending on the workflow you use.

 

"With great power comes great responsibility" -Uncle Ben - Spiderman...

Edited February 5, 2015 by siddharthkolte

[Crazy Homeless Guy]

Just because you can doesn't mean you should.