Ellipsis-Problems with dimensioning

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Tutorius
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Joined: Tue Dec 13, 2016 7:34 pm

Ellipsis-Problems with dimensioning

Post by Tutorius »

Hi,
i need some sketches with only one sllipsis in each. The values of these ellipses should be changed parametricaly by a spreadsheet.
The problem is the dimensioning. The ellipsis gets into a unknown state when reaching the form of an circle.

After the values are the same, only the major dimension can be altered, the minor is no more changeable.

Freecad is in version 0,20, build 25844 GIT from 2021/09/25

Any way i can avoid this?
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regards

Hartmut
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Shalmeneser
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Re: Ellipsis-Problems with dimensioning

Post by Shalmeneser »

MWE ?
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papyblaise
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Re: Ellipsis-Problems with dimensioning

Post by papyblaise »

modify the 2 axes until equal, it works
modify the "small" to be "bigger" than the big one, more, problem of position of the foci which are on the "large" of origin and should "pass" on the "small" of origin

am I clear :?: , I also mix my neurons by rereading myself :!:
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Tutorius
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Re: Ellipsis-Problems with dimensioning

Post by Tutorius »

The fuselage of this plane is made of eight profiles, each declared as an ellipsis.
The parameters for these ellipses and many more parameters are held in the spreadsheet.

It is not possible to change the "direction" of such an ellipsis by changing the sizes. When changing higher to lower value or lower to a higher value, the sketch is getting wrong.

In this case here, there is no need to change the directions of the ellipses, they are all "standing", but would be nice if there will be a ellipsis-version that can change the direction of it or can work with equal values and be later changed to unequal values...

Greetingt
Tutorius
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regards

Hartmut
chrisb
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Re: Ellipsis-Problems with dimensioning

Post by chrisb »

Depending on the controlling values you could rotate the sketch by 90° thus the major radius can stay major, the minor stays minor.
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Tutorius
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Re: Ellipsis-Problems with dimensioning

Post by Tutorius »

chrisb wrote: Thu Oct 21, 2021 11:51 pm Depending on the controlling values you could rotate the sketch by 90° thus the major radius can stay major, the minor stays minor.
OK, i will try this... Something like:

Rotate-Value=(if x<y)*90

And a swap of parameters:

X2=x*(if x>=y)+y*(ifx<y)
Y2=x*(if xY=y)+x(if x<y)

will give it a try...
Thanks for the hint...
regards

Hartmut
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