error in reflection

[cmjohncheng]

reflection got some problem, that box is mirror mtl, set 1 and set 2 material is same setting, set 2 that green and purple color box in vray object properties, visible in reflections and visible in reflactions uncheck. but reflection still show some problem, is it beside move that green and purple color box, but can dont reflect it? i know coz by that 2 object is overlay, but both of them already set to visible in reflections and visible in reflactions already....

btw, invisible to camera also will show some error

[cmjohncheng]

here is scene file
http://www.archcg.my/file/boxtest.rar

[Svetlozar Draganov]

Overlapped geometry can always cause render errors, even if it is hidden for reflection/refraction/camera etc.
Vray expect to receive the correct geometry in order to give you the correct render.

[cmjohncheng]

thanks for reply, beside edit model, any other method can solve it?coz some tree's leaf model overlap, hard to solve one by one...
now i got one glass building, infront of it i want to show a park(inside got many tree), but i dont want that glass reflect the park(now glass show many black noise like image i attached).
if render 2 times sure can solve it, just try to looking better method..

[Svetlozar Draganov]

You can try to increase Secondary Raytrace Bias to 0.1 / 1 / 2 - sometimes this can help you to solve such artifacts.
Activating Back Face Culling also can help for such issues.

[cmjohncheng]

thanks! cant solve all the black noise in my actual scene(maybe too many surface overlap), but much better already.

[Svetlozar Draganov]

Can you post a render before and after ?
I am just curious how much of this dots are cleared.
Have you tried both options together ? Back Face Culling and Raytrace Bias .