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Sayla
12-15-2011, 06:04 AM
I've been setting out laminations and various curves using Autocad 2010 and I must say that the spline tool is very user friendly.
I've read on this forum about people having difficulty putting bsplines through fixed points, but this program does it with ease, and.....to my surprise..... will quickly generate offset bsplines that are both concentric yet parallel, matching the way timber laminates around curves - here's a stem example that I've just done so I can see and experiment with how the laminations will run

http://i283.photobucket.com/albums/kk301/south-seas/stem.jpg

to the computer nurbs - happy bsplining

sayla

Jim Ledger
12-15-2011, 08:31 AM
Nice, but I'd make that scarf longer.

Sayla
12-15-2011, 06:27 PM
Yeh - thanks
The stem piece sort of approximates the original solid piece stem components (there's lots of bolts) - but good point, doesn't look balanced in strength when laminated

I increased the stem by one station and let the keel out to approximate the original length - looks better I think - I'll keep the original bolt set up, or near to

I have already drawn the framing on another program - but I find the bsplines and editing on this one to be awesome

http://i283.photobucket.com/albums/kk301/south-seas/stem2.jpg

Sayla

woodpile
12-15-2011, 06:40 PM
NURBS...non uniform rational b-spline, haven't heard that since the previous aerospace job, was a great tool for developing airfoil shapes.

fair&fair
12-29-2011, 02:18 PM
The problem with splines in Autocad is that they are basically useless after you have drawn them. Once you draft your spline, when you select it in the future, it will be comprised of a zillion different control points, which makes tweaking that line in a meaningful way (read: keeping it a fair curve) impossible. The alternative is to use a Polyline and then "spline" it. You do this but executing the "pe" command and then choosing spline in the options list. doing so will give you a curve that is the same as a spline, but with as many control points as you originally used to lay out that line. Once you offset that curve, the offset curve will have many more control points, but such is life while using Autocad...