New tool: Bézier's and Burmeister's "French" curves

[Former user]

In order to be able to recreate historical patterns sometimes is necessary Bézier's and Burmeister's "French" curves rulers. If it is possible to recreate them in your Software, it would be great help for cosplay, theater and investigate tailors to do their work.

More information: Bézier's curve: https://en.wikipedia.org/wiki/Bézier_curve French curve: https://upload.wikimedia.org/wikipedia/commons/6/60/L-Zeichnen2.png

[Roman Telezhynskyi]

http://valentinaproject.bitbucket.org/Adaptive_Subdivision_of_Bezier_Curves.html

[Roman Telezhynskyi]

We use this algorithm. I don't understand your request. Even if we name them "splines" this means nothing, they still are Bézier's curves.

[Roman Telezhynskyi]

@tusuzu, i don't understand this request.

[Susan Spencer]

This is a request to design curves which blend into the adjacent line or curve.

[Susan Spencer]

Issue #395 Create Curve tool which uses point as control handle

#395 can implement #394

Or, we can make a tool where two segments are selected and a curve is created between them. The length of the control handle is adjustable, and the angle at the begin and end of the curve is given.

[Roman Telezhynskyi]

Or, we can make a tool where two segments are selected and a curve is created between them. The length of the control handle is adjustable, and the angle at the begin and end of the curve is given.

Can you provide an example, because i still can't imagine this?

[Susan Spencer]

Attached an image file for possible GUI dialog for French Curve tool. This is an important tool. This technique is used frequently in manual patternmaking.

User selects two segments adjacent to the desired french curve. Each adjacent segment can be a line or a curve. User selects Begin and End points on the adjacent segments. User can adjust the length ratio of control handles.

The angle at begin & end of french curve is determined by the tangent at the begin and end points on their adjacent segments. The angle cannot be adjusted.

[Roman Telezhynskyi]

You are trying to make the French Curve tool based on current way we deal with curves. But what if i will tell you, we could make the angle value as formula.

[Susan Spencer]

Side discussion: Angle value as a formula, similar to these issues?
Issue #318: Add 'Angle of Line' user function
Issue #317: Add 'Angle of Vector' user function
Because we could really use these to accurately make armscye curves.

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[Susan Spencer]

We should include a 'French Curve' tool, even if it implements a special case of a more general tool -- it would be a time saving short cut that would be appreciated by most patternmakers.

The user only has to indicate the adjacent lines or curves and doesn't have to calculate the angle. Many curves can be made this way.

And it is standard practice to use a 'French Curve' ruler for drawing curves between existing lines and curves.

[David Arnold]

I can give a perpendicular point of view from my Autodesk Inventor experience: There is a restriction called "tangent", which is kind of similar to this. So when I have a curve or an arc, I can then set this restriction which automatically fixes the angle to 180 respectiv to the tangent of the loose point. I think in pattern making, other than tangent restricted, for example in armscye we also deal with typically 90 degrees angles respective to the tangent of the loose line. This is an helpful "restriction" for trueing. Another interesting variant, besides a 180 and a 90 restriction would be that I can well define two (or more) spots where the restriction is such, that the sum of respective angles must add up to 180. This would provide an elegant way of automatic, adaptive trueing.

Note that inventor works with a second layer called "restrictions" which helps define (or "restrict") singular aspects of a more general "tool".

Just my 2 cents.

[Roman Telezhynskyi]

Duplicate of #395.