There are several probable reasons: 1. To simulate with a build file, the user typically uploads a zip file containing the machine instruction file and an STL file containing the part geometry. The STL file is used to determine the part’s outermost contours. The build file processor used to assume that the part geometry in the STL was aligned with scan patterns in the machine instruction file in the X,Y plane. This was a bug which has been fixed in the cloud as well as in the alpha-1.1 release of Additive Print 19.2. The part geometry and scan patterns are now aligned during processing in X,Y. 2. In the case when the scan patterns are exceeding the part boundaries. Either the geometry in the STL file needs to be scaled to match what is in the machine instruction file or the geometry orientation needs to be rotated to match the machine instruction file or both. I can’t tell which without further investigation but this should be enough for the user to get a successful simulation. 3. Note that for Scan Pattern simulations, the solver is currently not checking for scan lines outside of part boundaries. This is a bug that has been added to the solver teams backlog. To get a successful simulation: When using Desktop Additive Print: One would need to alter the STL file to match the size and orientation as well as the position in the X,Y plane to match the scan patterns in the machine instruction file. When using Cloud Additive Print: One can disregard the position in the X,Y plane but will still need to match the size and orientation.