Hi, I am testing open source CAD import for open source FEA & CFD. Acoustics, Bio-Medical, Vehicle CAD for Dynamics such as Off Road Vehicles, etc. I need interesting CAD test cases for everything from acoustics of animals to off road high speed impact. All I need is that the CAD is stitched up when possible. STL is very tricky to convert to solids sometimes but there are work arounds. Pretty much there are 2 levels: 1. Highly representative CAD test cases, but simple, for multi-physics quick what if tests, could be coupled CFD into Mechanical FEA. For example, super clean CAD of 2 gear teeth on a shaft meshing. and 2. Very complex CAD but super clean with no gaps for the Bigger Picture complex analyses. For example, how much computer power do we need to solve more complex large CAD models. More interested in mechanical design but my hobby is the CFD and acoustic analyses of fish swimming. Hundreds of millions of years taught the sharks far more than we know, may be? Very Grateful for any test cases you are happy to share. I am looking for perfect CAD please. Thanks, Simon. I used to be sjs_Fish1 but lost my log in.