Parametric horn

[jeremiahrose]

Hi there,

I'm trying to figure out a way to model a parametric exponential horn in Fusion 360. I've done this before in Sketchup using the Ruby API, but Fusion 360 is so fundamentally different that I'm not sure where to start.

Basically, I want to create a pipe that follows an arbitrary 3d spline curve, and then scale the pipe at various points along it's length so that it expands exponentially according to a given expansion equation.

I've tried using the sweep tool to make a curved cylinder, but this cannot deal with any sharp corners - "the body would intersect itself".

I've tried using the loft tool, but this also doesn't deal with sharp corners well - the resulting curved cylinder is folded in on itself at sharp corners.

The pipe tool works well, but I can't find a way to create a tapered pipe or to scale a single segment of the pipe so that it connects with other segments smoothly.

Any suggestions would be greatly appreciated, I am stumped.

[Anonymous]

Can you post an image of result you are after?

[jeremiahrose]

Here is a simple example horn made using a ruby script in Sketchup. I could just import it as a mesh, but I want to do this natively in Fusion360 so that I can take advantage of its parametric workflow, and to properly fit the horn with other features of the design.

[davebYYPCU]

I have done these in fusion, freehand, as I am not aware of the equations you want to input, 

Certainly we can ask for impossible shapes where it may fail, but these looked the same as the example.

Sweep will handle sharp corners, but curved paths and self intersections won't work.

Two Sweeps and a Loft with shell or not.....

Sweeps are using the taper angle...

Centre line Loft needs 3 sketches....

[jeremiahrose]

Thanks Dave for your help!

I've also managed to make some freehand horns, the problem is they are all conical horns (like in your examples) - that is, they have a constant rate of expansion. As stated earlier, I'm trying to make horns with an arbitrary rate of expansion, given by an expansion equation. So either continuously, or at set points along the curve, the radius of the horn is determined by this equation.

I've tried approximating an exponential horn by using the loft tool to make a series of smaller horns joined together, however this approach takes a very long time to implement manually, and the resulting objects don't work with the shell tool...

[Anonymous]

Hi, it was so long time ago, but I'm very interested, can you build the horn with exponential function?

[davebYYPCU]

This fella is going down the same track, Check here.

Might help....

[Anonymous]

Thanks!