Why does this sweep not work?

[gregorylance]

I'm extremely new to Fusion 360 and am struggling here. I'm trying to create a face cover for a handheld device, when the cover wraps around the sides of the screen. To do this I set up a sketch to represent the side wall and attempted to use a sweep to "extrude" the side of my face. However the sweep will not work and I can't figure out how to fix it. My goal is to set this edge up on the side, set a similar one up on the front, and then connect the two via revolve or loft.

Here's an image and I've also attached my model.

[Drewpan]

Hi,

I would strongly recommend that you do the embedded tutorials in the Fusion Documentation and also some of the

Self-Paced Learning to help you to learn fusion faster and better. They can be found here:

It is also much easier for the forum to help you if you attach your file AND a screenshot of what you want to achieve

and what the problem is. You can create a file to export like this:

Time spent on the tutorials and self paced learning will not be wasted. Also check out the three RULES that are pinned to the forum for further guidance.

The error message tells you where the problem is, there is a sharp corner. It will probably be the point where the

curve meets the straight edge. Simply put a Tangent constraint on the line and curve and it should work.

Cheers

Andrew

[TrippyLighting]

If splines were the proper way to capture the geometry, then you would be using way too many spline points. I would suggest you start with lines and arcs and only when hat doesn't work use a spline in places but not for the entire shape.

[TheCADWhisperer]

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@gregorylance wrote:

I'm extremely new to Fusion 360...

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1. Make use of obvious symmetry about the Origin.

Having given that tip, I recommend that you start with far simpler projects and post your progress for guidance by the experts here working your way up to this complex geometry.

[gregorylance]

Thank you for your input. I am going to walk through those tutorials. That being said, just for the sake of closure I did want to follow up here. First, here is an example of what I'm trying to achieve:

I would like this outer section to extrude downward at an inward angle. I created the "front" sketch to be the path on which this would extrude.

Per another comment in this thread I replaced my splines with arcs, and per your comment I added a tangent constraint between the straight line on which I'm attempting to sweet and the bottom curve. However it still did not work, it gave the same error. If I'm just in over my head here I can give up; I understand I need to do the tutorials and I intend on doing them before completing this project (I'm sure I'll start from scratch after doing so). But in the interest of learning I'm still curious conceptually why this doesn't work. 

I've even tried doing a sweet on just the bottom face, which I would think would have to work because it's flush with the line that the error claims it's intersecting. How can it intersect if it's just working from it?

[TrippyLighting]

1. Ideally, the sweep path is captured in a sketch that includes the sweep path only.

2. The sweep profile should be perpendicular to the sweep path.

Neither is the case in the design you attached. 

[gregorylance]

Maybe (probably) I misunderstand the full concept of a sweep path, but the sketch that contains the path I'm trying to reference only contains that:

The light blue area is the only thing within the "Front" sketch, which I have configured to be displayed in the screenshot above. I did some tutorials on the sweep function and this was my understanding...you'd create a sketch to define the path, then reference that path.

On #2 when I first started trying to figure out how to "extrude at an angle" I found multiple posts where sweeps were recommended for it, so I didn't think they were restricted to being strictly 90 degrees, which is what I imagine you mean when you say perpendicular.

[TheCADWhisperer · Accepted solution]

@gregorylance 

It is unclear to me what you are trying to do, but try turning off Chain Select when selecting the Sweep Path.

[gregorylance]

I'm trying to extrude that outer rectangle downward and inward at an angle. Unselecting the chain selection option seems to have worked for me. Thank you.

[TheCADWhisperer]

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@gregorylance wrote:

I'm trying to extrude ...

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I thought you were attempting a Sweep, not Extrude?

[gregorylance]

So, my original goal was to "extrude" that section downward at an angle. I did some Googling to do that and found out that you can't extrude at an angle, you can only extrude something on a perpendicular plane. So extruding at an angle isn't possible. From my Googling the suggestion was to use a sweep, and that's what led me here. Trying to use the sweep to "extrude" (again, not in the official command sense but rather in the general extending the face of an object) the section was failing, and that's why I made this post.