topic Re: Create parametric shell around negative space? in Fusion Design, Validate & Document Forum

Create parametric shell around negative space?

ThomasF7WDB — Sun, 07 Jan 2018 17:33:41 GMT

I am a hobbyist with a smattering of 3D modeling experience, but new to Fusion 360. I am struggling with a workflow issue.

I need to make an alignment guide where the XY interior spaces need to have precise measurements. It is simple - a hole with a specified number and size of slots extending away from it. Then I need to create an outline of specified wall thickness around that space. Then I can extrude the whole thing into Z.

I can do this easily using several different workflows to make a specific example, but am at a loss of how to make this work in the general parametric case.

Thanks,

Thomas

Re: Create parametric shell around negative space?

TheCADWhisperer — Sun, 07 Jan 2018 19:37:02 GMT

Can you Export an example file and Attach it here?

Re: Create parametric shell around negative space?

ThomasF7WDB — Mon, 08 Jan 2018 00:53:06 GMT

Yes, something like this.

The items I need to set parametrically are the inner diameter, number of slots, length of slots, and wall thickness. Optionally, the jig height and size of relief cuts would be good to set as well.

Re: Create parametric shell around negative space?

TrippyLighting — Mon, 08 Jan 2018 01:10:43 GMT

The original Fusion 360 file is needed in .f3d format. Here is a link that describes how to share a model.

Re: Create parametric shell around negative space?

ThomasF7WDB — Mon, 08 Jan 2018 01:33:14 GMT

OK, here you go.

Mind you, I haven't even attempted to make this version parametric, it is just a quick prototype of the result I want.

Thanks,
Thomas

Re: Create parametric shell around negative space?

TrippyLighting — Mon, 08 Jan 2018 02:03:15 GMT

Your design is already parametric. Because you are recording the design history (timeline) and have used parametric dimensions in your sketches and parametric features to create your geometry.

There is some more work to do as your sketches are not fully constrained and dimensioned but its a good start. Parametric really means that you can go back and change these parameters that drive you design.

You are not yet using user parameters for it, but it is parametric.

Re: Create parametric shell around negative space?

ThomasF7WDB — Mon, 08 Jan 2018 02:36:16 GMT

Sorry, I guess I am not expressing my question well. I know the parameters are captured as part of the design. I also know that when I go in to change them, the model falls apart.

Naively throwing constraints at the workflow in that prototype is very unlikely to solve my problem, as I know it is not well organized for that.

What I am looking for is general suggestions on improving the workflow for something like this so that the constraint network isn't a mess. That is why I was wondering if there was a way to wrap a shell around a negative space - that would greatly simplify the process. Of course, I am open to any suggestions that are more in line with Fusion 360 idioms, as a large part of my goal is to learn Fusion 360 better. Otherwise, I would just manually knock out the half-dozen or so variants of this I need, or script it in OpenSCAD.

Thanks.

Re: Create parametric shell around negative space?

TrippyLighting — Mon, 08 Jan 2018 03:04:20 GMT

Attached is a start.

Look at the user parameters.

Look at the dimension in the sketches.

Walk step by step through the timeline.

The reason I am making the disk in the beginning and then split it of in the end and remove it is because Fusion 360's retarded pattern and mirror tools do not allow to automatically combine the created geometry.

Re: Create parametric shell around negative space?

ThomasF7WDB — Mon, 08 Jan 2018 04:32:55 GMT

Thanks! That is very helpful. Thanks for your patience. 🙂