I have a piece of clothing that when I render it in PP2014 with the default lights it has a shadow around all the polygons so that it looks like the material is full of squares.

What causes this?  I tried changing the crease angle to 20 then to 120 (default is 80) but it seemed to have no effect. 

Ambient occlusion seems to make it worse.  No shadows on will fix the problem but it solve the problem. 

Anyone know?

if smoothing enabled in render, maybe bad welds or very narrow pointy triangles.

check for bad normals as well.

Pretty sure all the welds are good and they are not pointy triangles but I can check the normals.

I had opened the object in UVmapper and saved it out without normals.  Don't know if that makes a difference or not.

Crease angle has to be set for each and every group in all Groups properties.

The free Scenefixer script from Snarly can help you with that.

Then in the render settings, you have to check (enable ) Smoothing in the render settings.

Also, sometime polys just go bad for no particular reason...it doesn't happen a lot but sometimes it just does. Delete the poly in your modeling app and replace/cap, perform your usual smoothing and re-uv map it in same app.

Does the material include displacement or bump? "Old-style" bump maps, where mid-grey means 'no bump', used to cause problems at polygon edges. Effectively, they were telling the polys to lift and separate. This may be worth checking if you're using an old product, or if your bump or displacement settings are extreme.

I can try the delete and replace but it's not a procedure I want to go through if I don't have to.

The material has both displacement and bump.  The bump map is mostly mid-grey.  I would not consider the settings extreme but I'll play with them. 

Thank you to everyone

You could temporarily remove the bump and displacement, as an experiment. If it fixes the problem, you know where to start fixing things; if it doesn't, you can move on to something else.