Modelling Challenge in Solids Modeling Posted September 28, 2018 27 minutes ago, elepp said: That's true and annoying at the moment. If I use push/pull on the top surface it disappears. Best way is to add a solid on top and combine the to volumes. It's also not very intuitiv that you can apply the boolean function of adding volumes together on nurbs surfaces. Yes, I don't think that's actually a bug that would merit logging. More like a limitation in what surface modelling can and cannot achieve.