Hi, attached is the problem i have met recently after i change all my object to matt object except car and people, when i press render the RGB Color is look like this image,
please help, thank you.
Hi,
Could you post a simple scene setup that reproduces the issue?
As far I can see, most of the splotches are in the area below the trees.
Is it better when you add an override mtl?
Thank you for your reply, i haven’t try the override mtl yet,will give it a try. 
at this point, i made my matte object by changing their Vray object properties, so may i know where should i apply the override mtl to?
Hi,
You can use the Override option in Global switches tab to add regular V-ray mtl. It will override the matte objects as well (they will still work as matte, but calculated using the new mtl.)
You can first try to override the leaf material only and run a test render again. I believe this will make the things better.