topic Re: How to model an object that is both cylindrical and asymmetric? in Fusion Design, Validate & Document Forum

How to model an object that is both cylindrical and asymmetric?

autodesk-kevinBNVH4 — Fri, 14 Aug 2020 15:09:34 GMT

I keep designing myself into a dead end. If I want to keep things parametric (no sculpting), how do I tackle this?

Can a revolved body (or surface) be manipulated in some way afterwards or is it always locked into the sketch that made it?

I keep trying things, like modeling a separate 'pourer' as a surface loft. Everything I do becomes a geometric abomination.

I guess my question is, using the solid and surface spaces, is this way harder than I think it is, and is a good reason to use the sculpt workspace?

Re: How to model an object that is both cylindrical and asymmetric?

TrippyLighting — Fri, 14 Aug 2020 15:31:53 GMT

Here's one way to do this.

Roll the timeline back and then step forward one feature at a time:

Re: How to model an object that is both cylindrical and asymmetric?

autodesk-kevinBNVH4 — Fri, 14 Aug 2020 18:34:11 GMT

I think you made it too easy by thickening everything after creating one surface. I'm interested in modifying part of a revolution. All I'm trying to do is create a "cup" with more than a basic shape and modifying it asymmetrically.

Heres a snap of my going nowhere attempt.

First I'm revolving over sketch of the wall, and then I'm lofting between two sketches, the lower sketch being nothing more than an arc intersecting with the body.

Maybe I'll attempt to first convert that body to surfaces and then keep trimming and lofting and probably make a huge complicated mess.

I've found myself going down this road because I have a lot of those dimensions as variables and I'm going to iterate and 3D print a bunch of versions.

Re: How to model an object that is both cylindrical and asymmetric?

TheCADWhisperer — Fri, 14 Aug 2020 18:39:40 GMT

@autodesk-kevinBNVH4

Can you File>Export your *.f3d file to your local drive and then Attach it here to a Reply?

Re: How to model an object that is both cylindrical and asymmetric?

TrippyLighting — Fri, 14 Aug 2020 18:54:14 GMT

@autodesk-kevinBNVH4 wrote:

I think you made it too easy...

I think you have too little experience to make that assessment 😉

Aach your model and I can show you how to make this controllable with user parameters, or without.

Re: How to model an object that is both cylindrical and asymmetric?

autodesk-kevinBNVH4 — Fri, 14 Aug 2020 19:02:02 GMT

attaching

Re: How to model an object that is both cylindrical and asymmetric?

autodesk-kevinBNVH4 — Fri, 14 Aug 2020 19:05:15 GMT

attaching

Re: How to model an object that is both cylindrical and asymmetric?

TrippyLighting — Fri, 14 Aug 2020 19:36:38 GMT

See the model attached. If I'd create the model from scratch it'd be slightly different.

I did not pay attention to the (unnecessary ?) component structure when creating sketches and geometry.

Re: How to model an object that is both cylindrical and asymmetric?

TheCADWhisperer — Fri, 14 Aug 2020 19:36:08 GMT

You only need attach once - everybody can see you reply.

1. I would fully define all sketches.

2. I would model full solid (no cup cavity) and then Shell.

3. I would then add the additional spherical material at bottom of shell cavity.

Re: How to model an object that is both cylindrical and asymmetric?

ritste20 — Fri, 14 Aug 2020 22:12:32 GMT

A lofted part through a couple sketches would give you decent control over the form of the cup without wandering down a mesh or t-spline shaped rabbit hole.

A simple shell feature would remove the volume and give a uniform wall thickness. See attached

Regards,

Re: How to model an object that is both cylindrical and asymmetric?

autodesk-kevinBNVH4 — Fri, 14 Aug 2020 23:30:57 GMT

I was so close! ( I hope you assign partial credit ) but I just wasn't thinking cut then loft. You even wired up the trimming surface to adjust to the width of the spout when I drag the points.

But now I'm not satisfied with that top inside edge - It looks chopped off and chopping the twist in the loft gives it more surface area than the rest of the rim. Maybe a fillet would work but it wont let me fillet the inside edge because it crosses the loft/cup border. If that doesn't work can the thickness of the loft be tapered at the point? I guess in desperation I could make an entire outside and inside surface (never use thicken) and then patch them together? Of course that would probably take me a few years.

Re: How to model an object that is both cylindrical and asymmetric?

laughingcreek — Fri, 14 Aug 2020 23:38:34 GMT

@autodesk-kevinBNVH4 wrote:

...that top inside edge - It looks chopped off and chopping the twist in the loft gives it more surface area than the rest of the rim. Maybe a fillet would work but it wont let me fillet the inside edge because it crosses the loft/cup border. If that doesn't work can the thickness of the loft be tapered at the point? I guess in desperation I could make an entire outside and inside surface (never use thicken) and then patch them together? ...

why not use thicken?

Re: How to model an object that is both cylindrical and asymmetric?

TrippyLighting — Sat, 15 Aug 2020 00:39:26 GMT

@laughingcreek wrote:

@autodesk-kevinBNVH4 wrote:

...that top inside edge - It looks chopped off and chopping the twist in the loft gives it more surface area than the rest of the rim. Maybe a fillet would work but it wont let me fillet the inside edge because it crosses the loft/cup border. If that doesn't work can the thickness of the loft be tapered at the point? I guess in desperation I could make an entire outside and inside surface (never use thicken) and then patch them together? ...

why not use thicken?

I did use thicken, but it looked odd with the thick wall so I chopped the top off 🙂

Does not look much better though.

Re: How to model an object that is both cylindrical and asymmetric?

TrippyLighting — Sat, 15 Aug 2020 01:12:37 GMT

Better ?

Re: How to model an object that is both cylindrical and asymmetric?

laughingcreek — Sat, 15 Aug 2020 01:49:01 GMT

well yeah. I was just wondering why the OP seemed so emphatic about not using thicken. Like was it a rule of thumb he had heard? some form of thicken (thicken/offset/shell) seems like the best way to go here. only way to insure uniform thickness around the spout area. the original product pictured solves the perceived thickness issue by turning the spout down.

Re: How to model an object that is both cylindrical and asymmetric?

TrippyLighting — Sat, 15 Aug 2020 11:28:44 GMT

@laughingcreek wrote:

well yeah. I was just wondering why the OP seemed so emphatic about not using thicken.

Sorry. Did not have my thinking cap on when posting 😉

Re: How to model an object that is both cylindrical and asymmetric?

chrisplyler — Sat, 15 Aug 2020 13:27:17 GMT

I did something kind of similar. Surface lofts (and a Patch for the bottom) then Thicken. I did not cut the top edge off, so the upper edge of the spout still leans out more.

A weird thing...some edits make the Thicken fail, so to make them, I delete the Thicken, make the edit, then redo the Thicken. I think it's odd that the Thicken will successfully redo after an edit, but the existing Thicken fails upon the same edit.

Anyway...

https://knowledge.autodesk.com/support/fusion-360/learn-explore/caas/screencast/Main/Details/b35285cc-2aca-486d-99f8-25a6c5b0656d.html

Re: How to model an object that is both cylindrical and asymmetric?

laughingcreek — Sat, 15 Aug 2020 19:11:09 GMT

@TrippyLighting wrote:

...Did not have my thinking cap on...

They are a burden.

Re: How to model an object that is both cylindrical and asymmetric?

autodesk-kevinBNVH4 — Thu, 20 Aug 2020 16:51:23 GMT

Ok after much struggle I finally finished. BTW the solution to the original question was trimming out a notch for the spout. This was probably obvious to everybody but me because I'm a total newb, but I think I've finally grokked the trim and loft way of things.

Unlike the suggested solution of a "L" cross section trim tool I ended up with a trim tool that responds to the shape of the spout and radius of cup, all controlled by dragging a point on a sketch. This was to better mate the spout to the cup shape.

I also ended up using an inside and outside surface to have better control over the spout shape, especially the top profile.

Now I can keep adjusting the spout length, width, height, pointyness in prototypes.