With the patch selected click the Edit Patch button. At this point you may want to uncheck the Lattice box under the Display section. Sometimes it gets in the way. Click Sub-Object and choose Vertices . Now we are going to straighten out the bottom Vertices a little bit.
Curtains seem to be less wrinkled at the bottom and more at the top.
There are a few ways to do this here's how I did it. Click the Move transform button. Click the Y-axis Restraint . In the Perspective view click one of the bottom vertices and move it slightly towards the center. Do this to all of the bottom vertices.