Wrapper material not reay transparent

[sakur4]

Hello,

I'm a beginner in Vray. I have been taught few days ago how to use Matte/shadows but I can't do want I would like :

Why ?
- I use Vray to add some furniture in empty house photos (jpeg).
- I'm trying to add some shadows to make it more realistic.

How ?
Adding a planar surface on the floor and walls composed of :
- One base material
- One wrapper material with matte / shadow / alpha (-1) ticked

Problem ?
- The surface is not really transparent, I don't know why.
- The surfaces are dark
- The next pictures will speak louder than words.

Hypothetical explanation :
- When there isn't any wrapper surface, there is nothing else : empty space. The wrapper surface catches some shadows, but I don't know where they come from....
- Lights create indesired shadows (not furniture)

Solution :
- I listen carefully to your advices and solutions.

Pictures :
Initial photo
http://www.noelshack.com/2014-31-1407003205-initial.jpg http://www.noelshack.com/2014-31-1407003208-render.jpg http://www.noelshack.com/2014-31-140...8-viewport.jpg
Viewport (wrapper in "orange")
http://www.noelshack.com/2014-31-140...8-viewport.jpg
Render
http://www.noelshack.com/2014-31-1407003208-render.jpg

[Micha]

First: your result doesn't look so bad. Easy solution: I would soft erasure the edges of the rendered areas and adjust the brightness in postwork. Advantage: faster done than looking for the perfect raw render.

[sakur4]

Thank you for your answer.

A post production in Ps can be a solution even if the color variation is critical (especially the clock's wall).

I watched many videos where wrapper material is perfectly transparent and I would like to adjust my render settings if its possible.

Using a light dome instead of GI and rectangular light could help ?
Adding some spotlight may distrub appropriate shadows.

[fpedrogo]

The reason is because the planes are receiving too much GI. You will have to go to the wrapper material and reduce the "Receive GI" option to .1 or less.

[sakur4]

Thanks a lot !
I reduce "Receive GI" and brightness shadows to 0.5
It look better, I can continue my work.

http://www.noelshack.com/2014-32-1407257747-render2.jpg

[fpedrogo]

It is looking really good! I can't wait to see the final render.

[Markit]

Hi every body! I've got the same problem with MtlWrapper transparency and decided not to start new thread for that.

I've tried to describe the whole process in pictures attached. The same workflow, but i have to put objects in natural environment. Wrapper becomes really transparent only when turn "Receive GI" completely off, but i still get white border around objects(pic #5 and lat attached image).
http://postimg.org/image/41c6pdb0j/
http://postimg.org/image/90y0i3np9/

I've tired "hundreds" ways to resolve this but no result. Maybe somebody have any thoughts?
will be rally thankfull for your help)

[Markit]

The problem with white borders appears to be in "affect background" option, but I don't know how to avoid it rendering with background bitmap.

http://postimg.org/image/f8j1z1gt7/

And MtlWrapper still not transparent... even receiving GI 0,1
I'm getting sick of it hope for your help...

[Markit]

Sorry)) I' didn't see that this is V-Ray for Rhino forum section. I don't know how to delete my post, so I create new one in 3ds max part.