Consumer product design - asymmetric surface cut help

[robque]

Hi everyone,

Hope all is going well.

I recently started using fusion, (coming primarily from blender) to be able to do some parametric designs.

I'm working on bottle design the shape is visible on the sketch of screenshot "SC2.jpg", I'm trying to generate some asymmetric cuts that start small on the sides and get bigger as they run through the front of the bottle. (Purple lines on the second screenshot).

I'm working with a solid, made by lofting a couple of sketches at different heights with rail guides.

Then made a sketch that was then projected onto the surface of the bottle (purple line) to make the the cut.

Methods I tried so far:

(Method 1 - Sweep tool) type Path + Guide Rail, the guide rail is elliptical (on the same plane) further away as it crosses the front of the bottle -> error message "The path is not smooth"

(Method 2 - Loft tool) a couple of profiles along the path with incremental size, -> error message "Rail is not smooth, try to make the rail tangent continuous"

Both fail even though the bottle sketch is well constrained, using tangents in every corner.

Was thinking of going the surface route and try again, but have dedicated 10h+ already, wondering if anyone has an insight on how this could be achieved, or if it's even possible using fusion.

Thank you very much for your help.

[SaeedHamza]

CAn you attach the model?
Go to file>export>.f3d and attach it to your next post.

[robque]

Hi Saeed,

Find it attached, thank you for your help.

Best,

R

[TheCADWhisperer]

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@robque wrote:

Was thinking of going the surface route and try again, but have dedicated 10h+ already...

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@robque 

Are you willing to start over from scratch with step-by-step instructions using what was learned from this initial attempt?

[robque]

Sure thing ! really willing to learn

[TheCADWhisperer]

@robque 

[robque]

Awesome, thank you for your patience and help. 👍

On that initial sketch, I used the outer ellipse overlap shape to loft upwards to the next sketch. (with the offset ellipses as construction lines), once that was done, I changed the outer ellipses to construction and the offset ones to solid and used a loft to remove a small portion as the base isn't flat. (not sure if this approach is the best one, or maybe making 2 separate sketches o plane z:0)

Noted on your tips: no mirroring in these sketches and better to use a 3 point arc than a circle and the trimming the unwanted segment.

Do you see any other way of getting those curved sides instead of using intersecting ellipses?

[TheCADWhisperer]

@robque 

I just assumed you had a logical defined reason for using Ellipse.

I just experimented sketch a 3-point arc overtop of the Ellipse and there is no measurable difference.

I prefer to use the most primitive geometry possible (a circular arc is more basic than an ellipse).

Do you have a compelling reason to use Ellipse for this geometry?

[robque]

No compelling reason, my idea was just to make it parametric in case the volume needs to change in the future.

As i said willing to learn, if there's a "better" or "less problematic" way of making these sketches I'm open to recommendations

[TheCADWhisperer]

@robque 

Then I am going to change to arcs.

[robque]

Thank you!

Was playing around a bit with the sketches, if it helps a little check this updated one i made.

[TheCADWhisperer]

@robque 

Examine the Attached file.

Next we will create the indentation in the front.

[TheCADWhisperer]

Calculate the fluid volume.

[robque]

that looks awesome !

Could you share your thought process and best practices when making the handle and the reasoning of going about this way?

are these types of designs best done with a surface design, I've been playing around a bit with it and seems to allow better topology.

The last one you sent had a fluid level, is there a way to check the volume of the fluid?

Thanks again for all your help.

Best,

R

[jlarsonLP454]

That is interesting about the ellipse offset - it's a bit concerning that you can get different results based only on click location, I'll have to remember that if I ever come across a need for an ellipse offset. 

Personally I use the mirror command in sketches all the time, but it can be a bit buggy on occasion. Fusion really seems to have a problem detecting that drawings are fully constrained when you have arcs tangent to other arcs and are using those tangent constraints to position the arc. I haven't really found a great solution to the issue - I can usually mess around with constraints to get a fully defined sketch but some absolutely refuse and I either leave them unconstrained or right click and "fix" one point which immediately solves the problem, though I hate doing that on general principal.

[TheCADWhisperer]

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@jlarsonLP454 wrote:

I haven't really found a great solution to the issue - I can usually mess around with constraints to get a fully defined sketch but some absolutely refuse and I either leave them unconstrained or 

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@jlarsonLP454 

That’s when you need to get more eyes on the problem. Attach file here that exhibits unexpected behavior. 

[jlarsonLP454]

Unfortunately they are work files that I can't share publicly. I did have one that I shared with Autodesk support and they recognized it as a bug and said they might fix it eventually. It's been about a year and still not fixed (I went back and checked that sketch with the latest version), so I'll just keep working around the issue. I submit bug reports to the support team pretty regularly.

[TheCADWhisperer]

@robque 

The handle effort was a trial to get compound curvature surfaces.

Extrude would not permit compound curvature. I guess maybe I could set up a Loft-Cut, but it was easier to do a couple of simple overbuild Surface - Sweeps.

I didn't add dimensions yet to fully define the Design Intent as the result was a change from your original design.

The technique for evaluating the Fluid Volume was shown in the YouTube Video.

I haven't yet decided how I am going to do the cuts that were the topic of the original post.

I think I want to demonstrate how to create compound curvature intersecting 3D projection curves as that technique is often needed in parametric organic shapes.

[robque]

Thank you for the explanation.

Any chance you could share how you made the handle?

Saw the video afterwards, gave you a follow and like.

Best,

R

[TheCADWhisperer]

Bump.

Just moving this back to the top because I had forgotten about it.

I need to get back onto the topic of the original problem description - the indentations in the "front".