topic Re: Constraint Help in Fusion Support Forum

Constraint Help

mouse51180 — Fri, 28 Mar 2025 03:12:06 GMT

Im trying to work on a piece to 3d print that will interlock with itself. I seem to have everything constrained except for some circles that will be used for some magnets and the vertical pieces of the interlocking parts. I am not sure how to properly constrain these to make this work.

I am also trying to use the sketch\scale feature on the bottom cutout parts, but they don't seem to be working as expecting and I think it's due to the missing constraints.

Re: Constraint Help

TheCADWhisperer — Fri, 28 Mar 2025 07:12:08 GMT

@mouse51180

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

I see a lot of missing constraints. Mostly Midpoint.

Why are these Construction lines showing as under constrained?

Could you be missing Horizontal and/or Vertical constraints?

Click and drag. What do you observe?

Re: Constraint Help

HughesTooling — Fri, 28 Mar 2025 09:28:19 GMT

Easier to draw one half only and not trim the rectangle. To keep parts central I've used midpoint and vertical constraints. (tip, if you start the Horizontal\Vertical constraint, hold the shift key and move the mouse pointer over the midpoint of a line you can pick the midpoint while adding the vertical constraint). I used a parameter (Clearance) to add clearance to the bottom dovetail.

From the sketch just extrude then mirror for the other half. You could use a pattern but Fusion doesn't have a way to automatically join patterned bodies. File's attached.

Re: Constraint Help

HughesTooling — Fri, 28 Mar 2025 09:55:07 GMT

Thinking about this a bit more and I've come up with a way using a pattern so you could create this with more than 2 sets of holes and dovetails.

Using parameters create a sketch like this that will stay centred using different settings.

Then an extrude and pattern faces.

Just adjust the count parameter for what you need. File's attached.

Re: Constraint Help

TheCADWhisperer — Fri, 28 Mar 2025 13:33:43 GMT

@mouse51180

You have been shown the correct technique by @HughesTooling but you should still strive to understand why your sketch is not fully defined.

I can see obvious omissions just from the image without even having the file.

When in doubt, click, drag, observe.

Re: Constraint Help

mouse51180 — Fri, 28 Mar 2025 23:17:44 GMT

Thank you for both your solutions. I think your second example is too advanced for my current skillset with Fusion and I am trying to replicate your first drawing.

My original thought was to do half and the mirror the drawing, but I was having issues getting the dove tail pieces to mirror and could only get the circle to mirror.

@TheCADWhisperer The reason my construction lines were constrained is because that is how I found I was able to get the dovetail pieces centered on the circle and still collinear with the top and bottom edges of the piece.

@HughesTooling I am still having issues just trying to reproduce your example. I'm not sure if I'm sketching this out incorrectly or just in the wrong order. Here are the three issues I am fighting with trying to find the proper steps.

1) If I make my outer parameter box 19x20 > create a circle on the midpoint of the top edge > remove the midpoint constraint > move the circle down 7mm...I cannot do a horizontal\vertical constraint on the circle as seen in your example.

(view in My Videos)

2) Im curious how you made the dove tails. I have been creating them outside the parameter and them used the midpoint constraint to attach it to the part. This seems to be defined at this point, but not I have an over lapping line. In your sketch you do not appear to have these overlapping lines.

(view in My Videos)

3) My last issue in order to make the interlocking piece... I was going use the sketch scale tool, but when I use that... the top and sides dont seem to adjust out equal distances as I would expect. The top clearance looks to be a larger distance than the side clearance.

(view in My Videos)

Thank you for the help in assisting me understand how to do the job right.