https://communities.bentley.com/products/geotech-analysis/f/forum/244244/positive-interfaceHi everyone, I modelled a volume pile embeded totally inside the soil and it is working without adding postive/negative interface. However, when I add interfaces by decompose the pile to surfaces, error 111 occurs (Soil body seems to collapse. Pleaseen-USTelligent Community 12https://communities.bentley.com/thread/762108?ContentTypeID=1Sat, 15 Apr 2023 15:08:48 GMT6dad98f5-dbc9-4c4d-a9ba-e9da8dc6aa8e:254fe669-c344-40fd-a556-a2b9d8d7637eFaseel Khan<p>Without the project it is difficult to tell why the soil collapses. One reason could be the interface properties.&nbsp;To assist you further please submit a service request. Then, one of our support engineers can help you in detail: <a id="" href="https://apps.bentley.com/srmanager/ProductSupport">https://apps.bentley.com/srmanager/ProductSupport</a></p><div style="clear:both;"></div>