Hawkeye

My Feedback: (27)

I need a little help from the CAD experts out there. I'm trying to draw airfoils in Autocad Lite to be sent to a laser service. They say that using polylines ends up pretty expensive, so they suggest making the curves as arcs. I've tried to use the co-ordinate points to make arcs, but they never end up being tangent to each othet. The only success I've had is with splines and I'm pretty sure they are polylines so that is out. Any ideas on how to do this?

One other question, do different laser services use different software? Is there a service that would economically be able to use the splines? Thanks in advance for the help.

...Steve

DICKEYBIRD

What on earth could be expensive about polylines? Are they telling you there will be extra CAD setup time for them to trace your polylines with line segments or something? I ain't no expert by any stretch but I do cut my own ribs & bulkheads from my own CAD drawings with a homebuilt CNC router. I generate my rib profiles in CompuFoil, save them as .dxf's, edit and add them to my plan in TurboCAD, convert them to CNC G-Code with Ace Converter and cut away. The polyline issue never comes up. Trying to draw an airfoil with arc segments would drive me nuts!

I think all airfoil programs generate the curves with a series of closely spaced X/Y coordinates with straight line segments in between. When they're saved out as a .dxf, the top & bottom curves are saved as seperate "multilines" (I think) but can easily be "exploded." Ellipses: now they're a different story, for me at least!

Beats me why it should cost more If you don't get a more intelligent answer than mine, ask it over in the Scratch Building & CAD forum; there be's some real gurus over there!