Our company designs round tube frames. To do this we create part files using the weldment features. We sketch lines for weldment tube profiles for the straight pipes, but insert part files for the elbows and tee fittings that are used. We do not break the link to the original part and use the Locate Part feature to position it within the weldment tubes.

When we do sketches to add or modify weldment tubes, these elbow and tee fittings scatter across the screen seeming to lose all location mates. When exit the sketch and force a rebuild (Ctrl+Q) they go back to where we mated them to.

Does anyone know why this happens and how to avoid it happening? We quite often use points on these elbows and tee fittings as sketch points, but cannot since they are scattering while in sketch mode.

Please help.

Thanks.