Black streaks on MR baked lightmaps

[pickle]

Hi,

 

I am baking lightmaps using mr with just fg enabled. The object being baked is a flat single polygon wall with a standard max shader applied.

 

FG setting are basic with a large radius and around 1000 samples.

 

The light is a Mental Ray area omni.

 

When i bake the light into this object I get black streaking and splotches (see attached image).

 

I have some internet models in the scene whihch may have modelling issues. Would this affect the baking though?

 

I have seen this question asked many times but never answered, has anyone experienced this before and found a solution?

 

Thanks,

 

Rich