Manual drag / duplicate along curve with tangency?

Hi all,

I’m wondering if there is a way to tell Rhino to rotate an object so that it maintains tangency while it’s dragged into place… for example, I’d like to position one of the blue ribs so that when I drag or drag+duplicate it, it rotates automatically.

ArrayCrv kinda does it, but not manually.

I looked for various “along curve” commands but didn’t see anything.

Is there a built-in function to do this?

OrientOnCrv will do, with option copy you can add as many as you want.

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Thanks! I’ll look it up.

Hi again encephalon -

Tried this out, but it’s kind of baffling as I simply can’t seem to get it to stop re-orienting my object; for example, below, I just want to be able to position the center rectangle along the top curve where we can see the points.

No matter what I try, though, it flips my rectangle upside-down in relation to where it starts (rectangle on left). I looked through the documentation but don’t see what I’m missing…

yeah, that is a bit strange i must admit, best you rotate the object first before you attempt it. you can also use OrientOnSrf which is a bit better allowing you to set the basepoint and an orientation, which is also a bit weird but works. be sure to make a baspoint on the middle of the surface or what i do is using the snaps between (which i have as an alias which then is also working in commands), just be sure to extract the middle isocurve that you can orient the object exactly along it.

the orientation would have to look like this

or ArraySrf which works when you know a specific amount or a specific distance, it works actually most intuitive since it also follows an at least for me understandable normal direction, meaning you would have to make the normal orientation upwards.

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Hi Turner,
OrientOnCrv with the Perpendicular is a good command for this.
The OrientOnCrv with Perpendicular can seem unpredictable at times, but there are a few recommendations to help you succeed.

  1. Draw your curve/surface/solid to oriented in the Top viewport with the World Top Cplane. This is the way it will be oriented perpendicular to the curve.
    (If it is not on the Cplane, use the RemapCPlane to remap it from 3D space top the World Top. OrientOnCrv will use your current cplane, but try that when you are pro.)
  2. Create the Base point with the AreaCentroid or VolumeCentroid command, our pick on a feature of your object that you want to orient to.
  3. Select the Transform menu ->Orient → Perpendicular to Curve (OrientOnCrv with the Perpendicular option.)
  4. Option: Turn History on before ending the OrientOnCrv command. This will tie the inputs to the result. If you scale, rotate or move your input to the Orient, it will update the result.

See the video here.
To practice, you can download my Rhino 7 3dm file attached.
OrientToCrv with Perp option.3dm (94.7 KB)

There are many ways to get OrientOnCrv to work, but getting a good result first and first most of the time are what these recommendations are intended to do.

Mary Ann Fugier
McNeel Technical Support and Training
Seattle, WA

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