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Lofts and Sweeps that fold back on themselves
steven_armstrong
Member Posts: 13 ✭✭
Hello All,
I am modelling an air cooled cylinder head. It is time to do the fins. I am using the outer edge of the fin as the guide. I find that if the curvature of the guide is too great the loft or sweep folds back on itself and fails. Should I be doing this a different way?
https://cad.onshape.com/documents/812e1b48d1f642ed1f9ad8df/w/f18e3a8396163861513668e6/e/9b6aed276b422a12477c493b
I am modelling an air cooled cylinder head. It is time to do the fins. I am using the outer edge of the fin as the guide. I find that if the curvature of the guide is too great the loft or sweep folds back on itself and fails. Should I be doing this a different way?
https://cad.onshape.com/documents/812e1b48d1f642ed1f9ad8df/w/f18e3a8396163861513668e6/e/9b6aed276b422a12477c493b
0
Comments
An alternative approach could maybe be to: 1) sketch the whole fin on the horizontal plane (same plane as your "Fin Guides Outer" sketch is using), 2) extrude up/down to create a constant thickness fin intersecting with the head, 3) use draft to create a taper, 4) fillet, chamfer, or sweep the along the outside edges as needed.
Website: ovyl.io
I now understand the proper use of guide curves. I have realised that to exercise full control of the loft there needs to be a guide curve for each vertex that needs to be controlled. In addition the guide curve form can't be in contradiction to profile start and end conditions. To do this fin in one go I need a start and end profile and a guide curve for 5 end vertices and two root vertices. That's 7 planes!