I built a tube chassis using 2d sketches on planes with 3d sketches connecting the various 2d sketches. Everything went fine until I went back to change something that has nothing to do with this 3d sketch that is failing. I changed some dimentions on another 2d sketch and the part failed to rebuild. When I continue and ignore solidworks crashes. When I stop and repair the first 3d sketch in the tree fails and when I investigate why it shows nothing wrong within the sketch. When you right click and click what's wrong, it tells you that it is missing the plane the sketch was created on. Why would a 3d sketch be created on a single plane? It doesn't make any sense. Does anyone have any possible answer?