topic Re: Help designing a simple coat hanger in Fusion Design, Validate & Document Forum

Help designing a simple coat hanger

whkiess — Sat, 05 Jan 2019 02:25:04 GMT

I'm having trouble designing a simple coat hanger using parametric design such that changing the width of the hanger causes the whole hanger design to adjust itself and redraw perfectly. Not just that, but the actual design itself is proving to be a headache. I've tried several methods but none seem to work. I especially have difficulties in getting the arc at the hanger end to draw properly, i.e. at a tangent with the top of the hanger. It doesn't need to be at a tangent at the bottom, it just has to look good, and at a width of 230mm a radius of 25mm seems to look the best. I also can't seem to get the lines to go black in the F360 design as I can't apply enough dimensions or constraints. The way I figure it is there is really only one dimension, that of the width of the hanger, everything else is derived or constrained to that.

How do I design this hanger? I started with the right hand outside triangle, then drew an inside triangle, then mangled the outside triangle to have an arc at the pointy end, then I mirrored it along the vertical axis on the left. I tried to do all this with only one dimensioned line, that being the outside bottom of the triangle which is half the width of the hanger. Everything else was a derived dimension or constrained to the lines one way or another. It just didn't lend itself to resizing based on the hanger width.

Re: Help designing a simple coat hanger

TheCADWhisperer — Sat, 05 Jan 2019 02:43:14 GMT

File>Export and then Attach your *.f3d attempt here.

Re: Help designing a simple coat hanger

whkiess — Sat, 05 Jan 2019 02:51:25 GMT

This is my latest attempt. I did not manage to get the arcs at the ends this time and the whole thing doesn't scale properly.

Re: Help designing a simple coat hanger

etfrench — Sat, 05 Jan 2019 03:01:46 GMT

Try this:

Re: Help designing a simple coat hanger

whkiess — Sat, 05 Jan 2019 03:41:29 GMT

Thanks for the suggestion, it looks very good. I could adjust it by making it larger and it worked fine, but making it smaller resulted in problems with the arc.

Re: Help designing a simple coat hanger

etfrench — Sat, 05 Jan 2019 05:29:41 GMT

@jeff_strater: This looks like a bug. When the hanger is resized from 100mm to 70mm, the arc is not drawn properly. When the hanger is resized in small steps (2mm to 5mm), it resizes properly to below 70mm.

Re: Help designing a simple coat hanger

davebYYPCU — Sat, 05 Jan 2019 06:00:21 GMT

Needs a dimension like this to stop that. Origins ae useful if you use them.

Might help.....

Re: Help designing a simple coat hanger

etfrench — Sat, 05 Jan 2019 07:58:49 GMT

Unfortunately, in my first file, the end point for the width line was not actually coincident with the origin. I can't explain why it wasn't

Here it is redone with the end point coincident with the origin:

Note: It still displays the same bug when resizing down more than 5mm at a time.

Re: Help designing a simple coat hanger

davebYYPCU — Sat, 05 Jan 2019 08:44:10 GMT

Haven't broken mine yet, OP wanted a 25mm radius, can jump 150 to 400 and works.

Might help...

Re: Help designing a simple coat hanger

jeff_strater — Sun, 06 Jan 2019 18:26:50 GMT

thanks, @etfrench. Yes, that is a bug. We've seen a few of these kinds of bugs before - where a large change introduces a bad result, but smaller increments do not. Good to have another case for the solver team to investigate. I've created bug FUS-45963 to track this example.

Re: Help designing a simple coat hanger

whkiess — Sun, 06 Jan 2019 22:22:36 GMT

Thanks @davebYYPCU, that's a nice looking design. It's missing the inner triangle though which also has to resize automatically when the bottom hanger width is changed. The idea is to extrude the sketch upwards to make a 2-3mm thick doll clothes hanger in various sizes. Would/could you provide the drawing file so I can have a look at how you drew it?

Re: Help designing a simple coat hanger

whkiess — Sun, 06 Jan 2019 22:33:06 GMT

@davebYYPCU What, you can have more than one origin? I didn't know that (still being a newbie) and I don't understand how this could help. Also, you've hit the nail on the head with the 'X' dimension. I don't know what this will be. Isn't it dependent on the width of the hanger and the radius of the arc at the end? Furthermore, the width of the top part of the hanger is supposed to be wider than the bottom rail (though I suppose it could be the same, but looks better when different). I also image the inside angle of the triangle should get smaller as the width of the hanger decreases. As you can no doubt tell, I don't have any engineering skillz and am muddling my way through this...All in the name of seeing the glint of happiness in the eyes of my grand daughter as she plays with these hangers in her toy store...

Re: Help designing a simple coat hanger

davebYYPCU — Sun, 06 Jan 2019 22:39:15 GMT

Sure, is attached, the hook remains tied to the top apex point, and just moves with it.

Offset the outline by xx and it will follow.

Re: Help designing a simple coat hanger

davebYYPCU — Sun, 06 Jan 2019 23:17:59 GMT

I know what you wanted, I left out the inside profile, cause I didn't need it to get the sketch to work, and didn't add it when it was all working.

Sketches don't have a history to read like a modelling timeline, so all you can do is play around in the Edit Sketch area.

Edit dimensions and the sketch will update for you. So change the bottom dimension, just shortens the width of the hanger, as it gets smaller, the hook lowers down, has to has no choice.

Let me know if you get stuck,

(PS I have seen that look in my grandkids

Re: Help designing a simple coat hanger

whkiess — Sun, 20 Jan 2019 00:23:34 GMT

Thanks to everyone who responded. Trust me to find a bug in the software.

Re: Help designing a simple coat hanger

chrisplyler — Sun, 20 Jan 2019 17:36:04 GMT

I started with this:

And then build the actual hangar around it. In the video below, I show you how to relate one dimension to another, such that when you change the length, the height changes proportionately. If you wanted, you could relate ALL the dimensions to the length in this way (using percentages if you like) and get the whole thing to scale proportionately with the length, although I assume you might want to leave the hook out of the scaling functionality, as you probably have some target hanger rod diameter to fit on. So you could set it up to scale to different sizes but keep a constant hook size.

Re: Help designing a simple coat hanger

jeff_strater — Fri, 15 Feb 2019 15:28:56 GMT

follow-up: This bug has been fixed in our internal build, and will be available in an upcoming Fusion release (I don't think this will make the very next one, but probably the one after that). Thanks again for reporting it.