Video : Offset Curve Dave Hack

Hey Dave! Thanks for giving a hand on this. but actually the outer curve is the positive offset of the original curve (middle). This is also deviating. ‘UNF’ = unfortunately

thanks a lot. You approach would work in a lot of cases. but I think there have to be a solid way of a ‘loose Offset’ command.

Agreed. If you need more accuracy, you always have the normal offset and the ‘lowered tolerance’ offset.

But, if you have a fully closed shape with only 7 control points, your result is what I would expect. Try to make the same curve with 12 control points (+/-) and it might work better. Also, don’t offset so far! That never works and gives you self-intersections.

1 Like

Hi,
Looked promising, but what to do if there are tangents involved ?

see my actual project item.

dave offset nasties workaround when tan involved.3dm (41.4 KB)

black is original curve with tangent top and bott.
red all cp’s selected.

blue ditto except tan points
Green Offset command…a mess !
Steve

Valid observations, but this technique is only designed for loosely offset curves where the concern is to keep the same number of control points. No other guarantees are implied or intended, regarding accuracy, mangling, or any other physical symptoms that may result. If dizziness or swelling occurs, please see a doctor.

A wise man once wrote:[quote=“schultzeworks, post:7, topic:18349”]
Its an estimate. The trade off of losing accuracy is that you get an exact number of control points, which is far better than doing it manually, point-by-point. That’s actually how I developed the technique. If you’re modelling an organic character, no one will ever see (or care!) about the resulting deviation.
[/quote]

Great little “hack-nique”, thanks for sharing.

Same thing here - Match. Then point edit if need be.

Hi, yup…did that, very acceptable result visually, it must suffice in light of fact that mathematically its not possible to attain the shape I had any other way.

Dave…thanks for the video and method, now added to most useful commands word doc :smile:

Steve

I have a vaguely related question: how does one invoke an AutoCad like command similar to ltscale? In other words, once assigning a linetype to a line, I can’t find a way to scale that line such that the dashes, dots, or other patterns will show while printing. This is something I don’t normally need to do, but has come up recently. Cheers, Rob

If I remember correctly, this is related to the drawing sheet and scale. In other words, the line width will change according to the scale settings. Any example? Screenshot? Not an intensive AC user but let’s see if I can help.

Or, you can try AC forum…

WOW, That’s absolutely elegant. Thanks very much for the tip!

I like seeing real world examples of commercial products that involved Rhino.

Thanks Dave/Schultzeworks : )

You are welcome. Thank YOU for not making me explain “it’s not supposed to be accurate” for the fourth time. :slight_smile:

1 Like

for those interested, I created a script that offsets curves loosely by offsetting the control points in a direction normal to the original curve, which has a different outcome then other techniques posted here. Script can be found here

For V6, could not Rhino’s offset command be changed to do this automatically?

Thanks @schultzeworks, this tip works really well for setting up curves used to create T-Spline objects from.

I mentioned it previously and did not hear back from any McNeel staff. Le’ts try again.

@pascal Any possibility of this?

Rhino 6 Beta just installed (why does the icon still say WIP?) Anyways, its two years later and I’m so proud to report that my suggestion has made it into the product! Who says McNeel doesn’t listen to users?

To be honest, they never acknowledged my brilliant suggestion or communicated that it was the least bit useful. As far as I know, this is a coincidence of biblical proportions.

3 Likes

Boneheads???

1 Like

Listening is just the first part. Acknowledging is the second part.

You never know they did the first without the second.