[Advanced] How to extrude with a function-defined angle over the path ?

[Anonymous]

Hello,

I am currently trying to achieve an advanced project for hydrodynamics using Fusion360 or any Autodesk tool since I have a student licence.

What I need to do is basically to draw a sketch, and to extrude it at a certain angle. This can be achieved using tools such as "loft" in Fusion360. The problem is, the angle of extrusion needs to follow a user-defined function, while "loft" would make the angle vary constantly from base to top.

Is there a way to achieve what I am trying to do with any of the Autodesk tools, or to write a script for this kind of purposes ?

Thank you in advance.

[davebYYPCU]

Probably.

what does , the angle of extrusion needs to follow a user-defined function,  mean in plain English?

Extrusions don't have paths.  Sweeps have paths, with guide rail and or surface with or without twist,

Generally both use the same profile, that can be modified

Loft has many rails, and can be different profiles.

Might help....

[TheCADWhisperer]

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@Anonymous wrote:

... I have a student license...

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As you can see from other response - your question is not clear.

Let me propose a question to you, "Why are you using Fusion 360?"

I ask, because you use only words in your problem statement.  If words alone were enough - we would not need a CAD program to communicate our design intent.

Can you File>Export and then Attach your *.f3d attempt here so that we can communicate with geometry along with words?

I assume you are a student.

Do you have web links to relevant research information, pictures, existing similar designs....

[chrisplyler]

The reason people seem confused is related to your terminology. In Fusion, an Extrude is a particular tool/feature. And no, it does not support any angle or other mathematical function. It's only straight out with a distance.

A different tool/function, Loft, supports Guide Rails. The default Loft produces straight edges between two Profiles, or curved edges if you use more Profiles. But you can define Guide Rails between points on the Profiles to control the path/shape the edges take if you want to.

Still, those Guide Rails are usually defined with lines/splines/etc., and are not easily set up to follow a mathematical function. There isn't any way in the default distribution of Fusion to just enter a function and get an appropriate spline graphed from it. There is an add-in/plug-in to generate a spline that way I think, but I'm not familiar with it. It is discussed and used successfully in this thread:

help-with-designing-a-rocket-nose-cone

[jeff_strater]

@Anonymous, when you say you want to extrude at a certain angle, do you mean at an angle to the sketch plane?  If so, Sweep is the tool that you probably want.  Define a second sketch, draw a line which defines that direction, use an angle dimension to allow it to be controlled by an expression, and use sweep.  I'll post a screencast explaining in just a minute...

[jeff_strater]

Here is a quick screencast to illustrate

[Anonymous]

Hello, thank you for your help, and sorry for not being very clear with my explanations.

What I need to do is basically the same thing as discussed in this thread : https://forums.autodesk.com/t5/fusion-360-design-validate/twist-while-extruding/td-p/6872419

The difference is that I need the angle of torsion to follow a mathematical function. I don't think Fusion360 can do this easily, and the only way I can think about is to draw the same sketch rotated at the desired angles on many offset planes, and to "loft" them so I get an approximation.

[Anonymous]

Hello, thank you very much for this link. I will have a look a the plugin and see if it is able to do what I am trying to achieve.

[Anonymous]

Hello, sorry for the vocabulary, I don't need to "extrude" indeed. What I need to do is to sweep over a straight path with a twist, while defining the twist angle with a mathematical function over the path.

This is useful for hydrodynamics because it would allow to draw optimally shaped turbines.

[TheCADWhisperer · Accepted solution]

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@Anonymous wrote:

... or any Autodesk tool since I have a student license. 

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Students can download Autodesk Inventor Professional for free from http://www.autodesk.com/edcommunity

Autodesk Inventor Professional has built-in functionality for 2D and 3D Equation Curves, or the curves can be imported from Excel spreadsheet.

Equation Curves  I am confident whatever you need to do can be accomplished.

Might even be far easier than what you think.

[chrisplyler]

@Anonymous

Here I use the Sweep tool, sweeping a square Profile along an Arc path, and setting a positive value for the Twist variable. So you can make whatever path you want (within the geometric requirement that the resulting Body doesn't ever fold back in on itself anywhere along the path) and you can also control that twist angle.

Now instead of a static value, you can make that Twist variable a Parameter, or even use a formula with or without Parameters. But I don't think you can use a FUCTION such that - for example - the twist angle changes dependant on the path position. Whatever you put into that field has to resolve to a constant value.

[chrisplyler · Accepted solution]

@Anonymous

You can also make a Sweep that uses a Guide Rail.

So if you can make that add-in/plug-in work to generate a Spline from a function, then use that Spline as a Guide Rail during the Sweep creation, maybe you can get what you're looking for.

[Anonymous]

Thank you very much, that sounds like what I am looking for.