The low resolution of the 3D-export causes significant distortion of the PCB shape.
easyEDA:
![easyEDA export:](//image.easyeda.com/pullimage/eTVtKIGN2PXw2DpJFVJuEEFrtshXU3HYiBxpxtuJ.jpeg)
third party (generated from gerber):
![thirdparty.JPG](//image.easyeda.com/pullimage/WVkbOVwQ6wC5S8qQksloXWC3OY1XVZMxMWqPaRqp.jpeg)
off topic: Generally, a STEP export with proper models like the 3D-view inside easyEDA would be nice.
Chrome
86.0.4240.185
Windows
10
EasyEDA
6.4.17