Matte object makes rendering much slower

[CG_Utopian]

Hi,

I am rendering a scene with a some objects are set as matte objects from Vray object properties, when i click on "shadows" in direct light section the rendering becomes very slow that is not possible to render anymore (30 minutes rendering turned into 20 hours rendering). is this normal? or am i missing something? or is it a bug?

[fraggle]

Did you tried to assigned Vraymatwrapper instead of using vrayproperty?

[chadstevens]

Could you supply a cut down version of your scene?