It is possible for your model to look flawless within your 3D design software but not after being uploaded to your Shapeways account. This can be due to issues with overlapping or reversed faces, loose shells, or other problems with the model's geometry. Netfabb provides a handy Auto-Repair option that can often fix these issues.
Note: Sometimes these fixes can lead to undesired modifications of the model. As always, it is best to review your model render after uploading it to your Shapeways account before placing an order.
3) Choose Extended Repair and clicked "Execute". This usually takes some time to process.
4) Once the repair is done processing, click "Apply Repair".
5) Choose "remove old part".
6)Review/rotate the repaired model to make sure it looks okay. Check for any potential missing details.