Fillet/Rounded corners issue.
That's a pretty good link Trippy provided, but yeah, with G2 smoothness, in calculus terms meaning the 2nd derivative of a curve is the same immediately adjacent on both sides of a point, then you get a nice uninterrupted light reflection from the physical body. Here is two splines with curvature comb turned on to show how they can be tangent at their meeting point (meaning 1st derivative or slope is the same, their curvature/2nd derivative can be different/not match up.
In the above example the two curvature values immediately adjacent to the meeting point are opposite in sign. You can visually see that in how the lower spline is curving upwards near the meeting point while the upper spline is curving downwards at the meeting point.
Zebra analysis is good at showing abrupt discontinuities to surface smoothness. Here is G0 (not even tangent to each other) between the "shoulder" patch and the surrounding surfaces in the example below:
Then G1
And finally G2
As a prominent contributor to these forums would say, you really want to go for G2 continuity between surfaces to get nice professional looking things, although I wouldn't obsess over it too much 😉
Jesse
I don't know why I didn't think of this before, but a great way to do this guitar is to make the entire perimeter with Trippy's method, and then just use the Patch patch tool and choose curvature (G2 at boundary) or tangent (G1 at boundary) for the large flat area. Here is Trippy's model with the inner faces deleted.
And the patch made (and with zebra curvature analysis turned on).
This is now a pretty darn fast method, and one doesn't have to worry about apposing faces being aligned with each other.
Jesse
Actually can get a decent sized fillet on the bottom (I believe the sharp turns at the "horns" probably significantly limit the fillet radius size). I first did a Patch patch with Connected/G0 option, then a Boundary Fill and filleted the solid body.
I've attached the .f3d. I'm really glad Trippy did this model for us so we can all learn a lot!
Jesse
I had not worked with the path environment and had not even though of doing it this way. Awesome and worth a K.U.D.OS
Collaboration is something that Fusion 360 is geared towards and this Forum 360 proves it!
IE is not letting me add kudos here, but if I could, well there'd be a kudo storm!!
Thanks all, really great work on this post!
Phil Eichmiller
Software Engineer
Quality Assurance
Autodesk, Inc.
Your approach is unlikely lead to satisfying results as it involves way too many faces and edges to manipulate..
I created this screencast to show my approach. My general guideline is to create as few polygons as necessary to "flow" around the perimeter of the guitar as that is really what defines the shape.
You can always add more edges if a particular area needs more definition. Add more eges as late as possible in the process.
The fewer faces and edes you have the quicker you can edit and make modifications.
I am not sure there are good car models in the Fusion Gallery, but you'd be surprised with how few polgons the sometimes complex shapes in vehicles can be created. But, again, that takes some experience.
With the the "Edit Form" dialog open, double clicking on an edge selects a whole edge loop.
Then while holding down the "Alt" key and start pulling on the manipulators and you'll exttrude from the existing ege loop. In this case you'll extrud the whole profile, not just the top face.