Fusion parametric workflow for asymmetric archtop guitar (ES-175 style) modelling

[S24JW1]

I am modelling a parametric archtop guitar (ES-175 style) in Fusion with an asymmetric body outline. I need best-practice workflow advice for:

1) building a fully constrained asymmetric spline outline without mirror symmetry,

2) creating construction-plane-driven cross sections for carved top/back, and

3) using loft with rails to generate clean, controllable surfaces suitable for manufacturing templates.

I have limited prior parametric CAD experience but am new to Fusion. What is the recommended Fusion-native workflow for this type of model?

[johnsonshiue]

Hi! Please take a look at Enzo Pascariello's project at GrabCAD. Please make sure your usage is consistent with the author's expectation.

https://grabcad.com/library/archtop-guitar-1

Many thanks!

[obulesub]

Hello, @S24JW1,

Just checking in—did the responses shared by @johnsonshiue help clarify your question?

If so, please consider clicking the "Accept Solution" button on the post(s) that solved your problem. Doing so helps others in the community easily find useful answers.

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All the best,

Obulesu | Community Manager

[S24JW1]

Hello,

I think the example model looks useful for drawing a surveyed guitar where the points are measured and are imported into the model to draw a spline of a known shape. I think this is the intent.
I’m wanting to build a design method where the spline points are parameterised so the shape can be changed.

I hope this makes sense.

[TrippyLighting · Accepted solution]

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@S24JW1 wrote:

...

I’m wanting to build a design method where the spline points are parameterised so the shape can be changed.

I hope this makes sense.

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It makes sense to a degree.
Splines are parametric in the sense that changing the shape of a spline with result in a change of the shape of the solid, or surface body created by that spline.

However, tying to use a user parameter driven approach where a "simple" change to a user parameter drives the change to a change in the shape of the final object is likely going to fail.

Splines have too many degrees of freedom that all would need to be properly constrained and dimensioned for that to work and then there are way too many dimensions to make that practical or useful.

If you can provide a specific example that would probably help clarify what can be done and what can't 

[programming2C78B]

You simply set your dimensions to work off a Formula instead of an absolute value. 

[TrippyLighting]

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@programming2C78B wrote:

You simply set your dimensions to work off a Formula instead of an absolute value. 

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It can be that simple, but more often than not it isn't!

[S24JW1]

Thanks, that’s really helpful. I’m not trying to fully constrain or mathematically control the spline — I’m using parameters just to define key positions (bouts, waist, neck area) and then letting the spline “fair” between them.

So it’s more of a guided shape rather than a fully parametric one. I’m expecting to refine it visually to reflect my design intent (and possibly against reference images), rather than have everything driven precisely by parameters.

[TrippyLighting]

In that case that is perfectly possible. Just use the timeline and make sure you have no yellow or red icons.

Use the Modify->Compute all feature after going back in the timeline and moving features, or deleting sketch objects. That will ensure the design is still sound.

[obulesub]

Hello, @S24JW1,

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All the best,

Obulesu | Community Manager