3-Point Arc Reference Line

[nuno_dias]

I came across this generic model adaptive family with a reference chain of lines driven by reference points. That chain of lines includes 3-point arcs driven by 3 reference points hosted in a circle. I’ve been trying to recreate these 3 point arcs with no success. Any thoughts how this is done? Thank you.

[martijn_pater]

Select the reference points and in the ribbon click 'show host', this should give you a better understanding of how each reference point relates to the other...

So first one is obviously the placement point at origin, second one above it has an offset by parameter 'H_axis_pier', the two circle center points are offset sideways hosted to that one (fyi you can set workplane x, y or z by tab-selecting a reference point when setting the workplane to place points), then there's the circles with radius parameter and some points hosted on the circles... think that's about it...

[nuno_dias]

Thank you for your reply @martijn_pater !

You described all the steps that I can actually do 😉. Then, there’s the rest that I can’t ☹️...Maybe I wasn’t clear enough… Sorry! Going from where you left: Those same points that are hosted on the circle, also drive a Reference 3-point-Arc (It’s coincident with the circle so it’s hard to see). I don’t know how to make that arc driven by the Reference Points. I can draw it but it has no connection with the reference points so, when I change Radius_top parameter, the arc doesn’t follow the points. Can you please follow up your instructions? Thx

[martijn_pater · Accepted solution]

You host 3 points on the circle (draw on face), these have their Normalized Curve Parameters set to 0.5, 1.0 and somewhere in between, creating the 3 points on which to draw the 3-Point Arc. You want to have '3D snapping' turned on for that.

[nuno_dias]

3D snapping, that's what was missing...

Great! Thank You!

[barthbradley · Accepted solution]

I know you got it all figured out now, but I just felt like playing around with Screencast this evening and your thread came to mind. Figured why not make it about your "3-Point Arc Reference Line".  😉  

https://autode.sk/3kMSCWh