a great App on Thingiverse that fix, and heal designs for 3D printing.

[faisal_nimri1 (faisal nimri)]

a great App on Thingiverse that fix, and heal designs for 3D printing.

https://www.thingiverse.com/apps/makeprintable

[Tomas_Vit (Tomáš Vít)]

I can recommend also free and very reliable Netfabb via Microsoft cloud services: http://netfabb.azurewebsites.net.

[faisal_nimri1 (faisal nimri)]

Unfortunately Netfabb doesn’t solve wall thickness issue