Bend Tube With Specific Radius

[davidbitton]

I’m trying to create a folded dipole for a Yagi antenna. It’s important in the design that the overall length of the tube stays constant. However Bend does nothing. Here is what needs to happen:

Here is a general idea

433_yagi.3dm (575.2 KB)

[milezee]

not sure if this helps, but maybe use the sweep 1 rail command, draw the rail exactly as you require, then a circle as your cross section curves, then sweep,

[milezee]

something like this, hope it helps

[davidbitton]

How did you get the line in the first place? As I said, total length is critical. Thanks.

[milezee]

just create a rectangle to work from, exactly to your overall sizes, then draw your curves to fit in

[davidbitton]

Based on the run length of the pipe?

[milezee]

as Richard says you already have some geometry to work from, but my personal method to do this would be start from curves like this, the red box used as a guideline to your sizes, then just sweep 1 rail with the black lines

[davidbitton]

I get the sweep (can also use Pipe). what I don’t get is making the line is the first place such that it linear size is specific.

[jeff_hammond]

try using the command SubCrv.

for example, here’s the full shape which is 22’ - 1/4" in length:

---

if i want 20’ worth of this curve, i can use SubCrv to achieve:

[milezee]

when using commands such as line, rectangle etc just type the exact measurements you require

[davidbitton]

i found better calculation tools that provide the length of the top piece
prior to the curve; cheating. I appreciate the push. Thanks.

[image: 433_yagi.png]