[Feature Request: Sketcher] curve along moving point or shape

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Eksterminator
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[Feature Request: Sketcher] curve along moving point or shape

Post by Eksterminator »

In doing precise engeneering I'm missing often feature of creating a curve along moving point or shape. I't's maybe not needed for art, but for engeneering is often crucial to have stuff done precisely.
The idea is that the kind of curvature would be saved as equasion taking points of support, lengths and point or edge where the movement cames from making You possible to see unlock and modify all the parameters (location of rotation support point's etc or resizing created pattern in direction dragged from selected point, You could name parameters like for an instance "amplitude" so it would be readable for people working on the same project in case of making sinusoide by spinning point around rolling circle along a line.
That's another feature I would like to see - rolling constraint that You can aplly on line so let me say constraining a line of radius length would slide it's all length when spinning the circle by 1 radian, or between circles like geared connection, just without gears, although this one would be also nice additional feature. So if You've got let me say 2 circles while one of them is 3x bigger rolling one circle around the 2nd one would make it doing 3 revolutions going all the way around (all points or lines supported on the circles would also spin).
Another feature - ability to use tangent constrain axis between multiple circles - selecting few and pressing 't'- would align them. The axle could be short line between them of size of average diameter with no points on it's edges, but You could add and move them to desired location. It's often useful as a line of symetric copy. BTW I have noticed a bug in FreeCAD 0.21 - symetric mirror copy when shape is on both sides of the mirroring axle is not working properly and when You use a point it says you can't do it (probably moaning about negative values of radius mirrored or something like that.

Coming bact to the curve feature it would be nice to be able to save it on the list of curves like kind of macros. The ones users would create most often could be included on the list in later on versions like spirals, sinusoids, zig-zag etc.
That kind of feature would open whole lot of new abilities. Constraining spiral on another spiral or something like that could make users able to make whole fractal structures in seconds.

There could be also fractal feature - You crate some shape and select on it points of sticking to another smaller or bigger same looking section just resized to match connecting points - You could select number of elements by each direction - like 2 bigger and 5 smaller.Image
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NewJoker
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Re: [Feature Request: Sketcher] curve along moving point or shape

Post by NewJoker »

Eksterminator wrote: Mon May 29, 2023 2:52 am BTW I have noticed a bug in FreeCAD 0.21 - symetric mirror copy when shape is on both sides of the mirroring axle is not working properly and when You use a point it says you can't do it (probably moaning about negative values of radius mirrored or something like that.
Sounds more like limitations but if it's a bug, please report it in the "Help on using FreeCAD" subforum and then on GitHub if other users confirm it.
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adrianinsaval
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Re: [Feature Request: Sketcher] curve along moving point or shape

Post by adrianinsaval »

sketcher is not meant to do kinematic simulation it's meant to do static 2D profiles, look into the nikra-dap wb instead for that.

with this in mind a "rolling constraint" does not make sense and will not happen in sketcher as there is nothing to roll, you could create a construction circle and constrain a point to be on this edge but I don't know if that will satisfy your need.
GeneFC
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Re: [Feature Request: Sketcher] curve along moving point or shape

Post by GeneFC »

Eksterminator wrote: Mon May 29, 2023 2:52 am
Frankly this sort of analysis sounds like it is much more appropriate for Mathematica or some other Wolfram code.

Gene
chrisb
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Re: [Feature Request: Sketcher] curve along moving point or shape

Post by chrisb »

Eksterminator wrote: Mon May 29, 2023 2:52 am The idea is that the kind of curvature would be saved as equasion taking points of support, lengths and point or edge where the movement cames from making
This sounds very much as if you were looking for addon "Parametric Curve FP".
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Eksterminator
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Re: [Feature Request: Sketcher] curve along moving point or shape

Post by Eksterminator »

Then You for the answers, but You're wrong telling me it's pointles.
If You do only simple geometries or some art graphicks precision indeed does not matter - you do staff just roughly having the needed shape and it's satisfying, but once you do precision engineering (as I do) any play will cause prototypes to fail shortly after production.
If You got a simple ROLL CONSTRAINT first of all You don't have to create 100s of extra constraints placing things in expected position messing up the whole scatch making it unreadable in case of copmplex designs (that I do).
If You want to for an instance design a simple rack making simplified model of circle and straight line it could mark revolution You need on the line with ease.
I don;t wan't to go into too many details but personally I needed this feature very often working on totally different engineering projects and TRUST ME A LOT OF PEOPLE BADLY NEED IT IN SCATCHER to make them life easier.

It don't has to be only circles but whatever curves or connected lines and circles so You can make very fast a desing of some rollers rolling along some curves.

Just check the animation on wikipedia, how I would see it (example of connected parabolas).
And the other feature like painting curve after moving point or shape after moving shape.
The red line on the animation would be edge of rolling of shape or as is if tracing point connecting the 2 parabolas.
https://en.wikipedia.org/wiki/Roulette_(curve)
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onekk
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Re: [Feature Request: Sketcher] curve along moving point or shape

Post by onekk »

Eksterminator wrote: Sat Jun 24, 2023 6:41 pm ...
No one as said that it won't be useful.

but this is not a CAD task, more a CAE task IMHO.

Said so Sketcher is made to produce 2D sketch upon you make faces, or use to be the starting point of other feature of a Solid.

So adding similar capabilities to Sketcher is simply a nonsense.

Do you have examples in commercial CAD softwares of similar feature? It will be interesting to see their implementation and see if something similar could be done.

FreeCAD has however Python scripting ability so something maybe could be done as an AddOn Macro or a WB.

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chrisb
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Re: [Feature Request: Sketcher] curve along moving point or shape

Post by chrisb »

Eksterminator wrote: Sat Jun 24, 2023 6:41 pm Just check the animation on wikipedia
This wouldn't be done in Sketcher. You would attach a point onto the edge and control with the MapPath parameter the position on the edge.
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