some objects appear darker in the scene and render
 

hello
please someone help because I am kind of going nuts
I have designed a robot hand (terminator looking) and at first everything was fine till I started playing around with the textures then the problem started...
the problem is now no matter what material I apply to all the parts, some parts look weird and really dark...
even if I remove the applied materials, most of the objects turn green by default but those ones with problem still look really dark and black
does anyone have any idea what happened that caused this and how can I fix it?

Its most likely a normals problem , if you post a pic it might help to be more specific but for now make sure all the normals are set to face and also try setting a normal angle of 30- 60.Im not sure what version of Mya you are using but if its 2008 or 2009 then you can do this under the normals tab.

thank you for the post
it was actually the normal problem
however since they objects are parented i have selecting the parent and reversing the normals...
because when i choose the parent and reversing normals it not gonna work since the children are selected too.
is there any way to just select the parent and reversing normals without unparenting the child. because if i do that they become messed up

you can select faces and reverse the normals on only those faces selected so convert the selection and deselect the children faces or just paint the selection on the parent or drag to select faces.

you haven't been playing with the initial lambert 1 shader have you?

thanks everyone
 

thanks guys
everything works out now
thanks