3-D Helix Section

[Secretagdan]

I have a section of a 'helix' that I need to create for a project. Is there a way to draw a helix with three given points along the helix? I suppoes that an example would be similar to a 3 Point Circle. Any Ideas?

[ReMark]

Draw the helix in 3D and then SLICE it.

[shift1313]

i dont know how 08 works but i believe there is a helix command. i know mechanical and inventor can do it. it will ask you for OD, wire size, number of coils and height i believe. 3 points would only give you 1 turn, is that what you are looking for?

You can do what you are asking with a spline by using 3 points and then extruding or sweeping along a path using that spline.

[ReMark]

AutoCAD 2007 on up have a HELIX command. Check the Help file on how to use it correctly.

[Secretagdan]

Okay. I have the Helix command, and for the most part I do know how it works. I do not think that a spline will work for what I need. If there is a way to make it work, I’m all ears.

I have an attached an illustration to show what I am looking for. This solid was created by drawing the 10' r circle, offset the line, extrude then subtract. Then I did the same thing for the circle in the front view & used the solid intersection command.

This would be all fine and dandy, but I have to have a piece of 1" x 1" aluminum bent to match what I draw. The problem with using this is the piece shown would be completely distorted from what would actually be bent. (The drawing shows the tubing as a trapezoid shape, rather than a square) Based on this the only line that could match up with what would actually be bent, would only be one edge of the drawn solid. Unfortunately, I have to match up some pieces that will weld to this.

This is why I thought that there may be something with the Helix command that may work, that is a little out of the ordinary. Is there a way to match this up, or am I just SOL? Is there a way to take what I have to create the Helix with the right 'turns' & ’revolutions’ to match my section?

[shift1313]

i see your issue now. I played around with sweep to see if i could get the alignment and twist angle programed in but never got it perfect. i ended up modeling the two "ends" and drawing the 4 guide lines by putting the two boxes where i needed them, drawing lines between their corners and making an ellipse, break the elipse in half and voila. sort of. ill keep messing with it and see what happens. speakin from experience bending 1" aluminum tubing around a 48" bender i made its very hard to keep it from twisting naturally. how are you going to have this bent? and did i read right this is a 10ft radius?

[Secretagdan]

Yes I did sort of get it to work; following something similar to what you did, using a circle. (I think that I cheated a bit, but I think this is going to work.) I took the construction lines from the top view & the front view to create intersections. I then used the intersections to set my ucs (3Point). From there I drew my circles & extruded them.

The nice thing about this is now our bender guy does not have to bend the helix shape, and can bend it using a standard radius. The only problem now is the joining Aluminum, now has some compound angles, which will not be very pretty to clean up.

The guy that does our bending has some sort of hydraulic equipment used to bend the aluminum or steel.

Yes that is a 10' Radius. The only time we have had problems with the bends, was when the radiuses were less than the 48" or so. A few ways to fix this was to use a heavier gauge steel/alum, or pack it with sand.