Building Curvature Pill / Racetrack Curves

now you are pushing it :wink: no just kidding, run CurvatureGraph, export or save as pdf set to vector that should do both without having to extract it first.

2 Likes

Bummer looks like exporting as AI doesn’t save the cones, but PDF works and that’s editable in Illustrator. Thanks again, this is a super useful tool to learn and use going forward!

Bringing this back to life just to see if anyone has any new tips or tricks :slight_smile:
Haven’t gotten into Rhino 7 yet so curious if anything new there would be applicable for this

New question: If I have a certain height for my curvature pill / bull nose [the red height line], how can I adjust CV’s and keep tangency while ensuring the curve end touches the max height?

Hello - I think I’d do this in two parts, meeting at the mid point of the red line.

-Pascal

Hey Pascal! Glad you got notified and good to hear from you!

My dislike with splitting and mirroring is that I end up having to eyeball the mirror plane and the curve gets a bit more bumpy than doing the whole thing at once

I could also Scale1D to adjust the height, but don’t know if that’s theoretically the best / cleanest way

Hello- you shiould never need to do that - the mirror plane is perp from the middle of the top line.
See the attached - maybe that is useful. Edit the blend on the cyan curve (BlendCrv >Edit) or move the white line.

BlendToMid_v6.3dm (37.7 KB)
@byvincewang - v6 file

-Pascal

1 Like

Thanks - to clarify I meant combs-wise I’m still left trying to get those to blend smoothly by eye. Any chance you could save your file as a Rhino 6 file? Haven’t gotten the time to upgrade yet!

Thank you for the Rhino 6 file! If I don’t build the full profile and instead mirror half, the point at the middle plane is never equal acceleration at least according to the combs, which you’re then left to eyeball

This is true. (however, at the scale you show, if you cat get that close I would say it is negligably off… but you are in charge. It can be further fine tuned as well)

-Pascal

select the second point of each curve, and make a scale using the gumball along the tangency, to have a greater space between the two points of each curve. this is supposed to correct that spike in curvature.

Another way of approaching this is to have a central segment as an arc, then connect the arc to the lines on each side, via a G2 blend; all symmetric along the centreline of the lozenge shape. The lines on each side need to be trimmed back from where the line meets the arc tangentially, to allow the blend to flow better between the line and arc.

One of the example pictures at the top of the thread has details that are concentric to the outer form, so by ensuring some of the end of the form is actually an arc, the offset detail looks right.

1 Like

Hey there Fares! I’ve never used Scale to move a point before, what’s the exact command to do so? I wasn’t able to figure it out. And are you able to move both points across the mirror plane equally / at the same time?

it is about positioning the gumball in the center.
I oriented the curves vertically to avoid repositioning the gumball each time I select a pair of points.
here is the video

1 Like

Got it now, that’s cool. Thanks for taking the time to screen record and post!

1 Like