I work for a company that restores aircraft and one of the problems I run into a lot in SolidWorks is coming up with decent loft surfaces to use as a reference surface for the fuselage or wing.Generally we have a set of ordinates that define X and Y on each frame or rib station. I need to turn these ordinates into a functional yet smooth loft surface. Can you guys give me some examples of the workflows you would use to do this?
Hello - I think I’d use some subset - pretty sparse - of the section curves to create the surface, and check the surface against the many curves. Does that get at what you are asking?
Yes and no, I understand what you are saying and it does seem a good way to go, it’s something I commonly do in SolidWorks. I’m looking for a more basic introduction to the process. I don’t want you to think I am asking you to hold my hand and waste your time, just something along the lines of how would you locate the profile sketches, would you use subd or a surface loft, what tools specifically would you use where, what would you use to check the surface smooth and how you would fix curvature smoothness. Again, I am not new to CAD, just new to rhino, so there is still a lot to learn and it would be nice if I could focus in on specific areas to learn first as part of a process that is useful to me.
Thank you for the response, btw.
Hello - Given what you show, I would start with a
Loft and see where that gets me - Loft prefers all inputs to have the same exact structure, so making all curves from an edited copy of an original is a good way to go. I would start with perhaps half a dozen evenly spaced curves (ignoring the hook in right at the cowl to begin with - that may be a separate surface.
What is the end goal - a full scale reproduction, an image, a scale model, or?
We restore airframes, the loft will be used as the main reference for all the parts of the frame, though in the case of the one above, that airframe is already complete. We have a number of restorations coming up that will need new lofts so this is in preparation of that.
are creating that surface from coordinates taken from a blueprint or from a scanned surface?
also will you be working in Rhino or Solidworks?
The numbers are taken from drawings called the Table of Offsets., they just list out the different X,Y coordinates for each frame station. I currently make them in SolidWorks but am looking for a way to make them more accurate more easily, which is why I am exploring Rhino.
so those tables reference the initial design, while you actually will restore already existing structure?
sorry just switched on my brain. usually there is quite a discrepancy between design and production, but here it has to be neglectable, otherwise that would be probably fatal.
Yep that would be bad.
With CurveThroughPt or InterpCrv you may need to the Knots=Chord option unless the input points have even spacing.