Hi I use geomagic software to add wallthickness (2mm) to my models. When i calculate the volume in geomagic everything seems right. However when the model (*.stl) is uploaded to shapeways website it is calculated as a solid model. The model doesnt have any intersections, spikes or other errors. This happened with me on several occasions. Please advice. edit: ive also calculated the volume in meshlab. And there WT also is also properly applied.