problem with render shadow with wrapper material

HI,
I use wrapper material to render shadow,
wrapper material param is below

MtlWrapper mmm {
base_material=base_xxx;
generate_gi=1;
receive_gi=1;
generate_caustics=1;
receive_caustics=1;
alpha_contribution=-1;
matte_surface=1;
shadows=1;
affect_alpha=1;
shadow_tint_color=Color(0, 0, 0);
shadow_brightness=1;
reflection_amount=1;
refraction_amount=1;
gi_amount=1;
no_gi_on_other_mattes=1;
matte_for_secondary_rays=0;
}
I give every material in the scene besides my target model a father wrapper materail.

Before I use wrapper. my render result is like this.


My scene is like this.

Then I attach wrapper material to every material in this scene except the sofa.
the render result is like this.


The color is much lighter than before, my goal is get a sofa looks just like pic 1.
I wonder why the sofa becomes so different, and what I can do to make the sofa looks just like before I use wrapper.

We can’t see your images if you posted them.

I update the question, hope someone can help me, really appreciate it.

Usually, disabling the “Matte for refl/refr” should do exactly what you want. However, I noticed you’ve already disabled it. Could you send the scene so we can take a look?

Yes, I have a better example, but the scene is very large.
here is the two different render result.



I adjust the wrapper param to make the png less exposure,
MtlWrapper mmm {
base_material=base_xxx;
generate_gi=0.5;
receive_gi=0;
generate_caustics=0;
receive_caustics=1;
alpha_contribution=-1;
matte_surface=1;
shadows=1;
affect_alpha=1;
shadow_tint_color=Color(0, 0, 0);
shadow_brightness=1;
reflection_amount=0;
refraction_amount=1;
gi_amount=0.5;
no_gi_on_other_mattes=1;
matte_for_secondary_rays=0;
}​

trust me, if I use the previous param, the png is much more white.

I want to upload the scene but the file is too large. can you give me a e-mail address.

aleksandar.hadzhiev@chaos.com