even when exporting the image at 7500pixels wide I still get those brick curvy lines

what's the deal?

So I have a complex grade that draped fine over the CAD topo.

I did a practice circle to drape over that. It worked fine and separated the terrain face.

I put in a roadway with entrance and parking and it will not create a separate face. the lines drape but that's it

any help??

I broke up part of it and it worked but when I did the next section, it did not work.