represent a circle with F-spline

[represent a circle with F-spline]

Thanks Heinrich for the comment, it is very useful information!

[represent a circle with F-spline]

I figured this out, I need to change the delta_x delta_y definition to make it work properly.

[FBSplineCurve]

On 12/18/2020 at 1:01 PM, Zhen Cheng said:

Never mind, I think I figured out, "tangent" is the angle (degree) of the  tangential line. It is not the tan(angle).

Hi Ceyhan,

May I ask a followup question? What is the definition of tangent in F-spline? Is it suppose to be the tangent value of the local angle? What if the angle is 90 degree (the tangent value is infinity)? In addition, how is the angle defined? The angle between curve tangential direction and x-axis? yaxis?

Zhen

 

[represent a circle with F-spline]

I have tried a simpler approach as a first step: Use delta-shift to deform the circle into eclipse, however this seems to not work as I expected, as shown below, the circle is not deformed into an eclipse, it seems that not all the points on the circle are shifted.

Could you help me to find out why this does not work?

 

[represent a circle with F-spline]

Hi,

I wonder if it is possible to come up with a F-spline curve that is exactly the same as a circle? Ideally this circle can be represented by 5 points with starting point and end_point overlapped with each other. The optimization I would like to do is to move p1 and p3 in x-direction, while the tangential direction at P1 and P3 is kept horizontal, and keep the area as constant.

Is F-spline the best option to achieve this? Would you help me to set up a quick example?

 

Best,

Zhen

[FBSplineCurve]

Hi Ceyhan,

May I ask a followup question? What is the definition of tangent in F-spline? Is it suppose to be the tangent value of the local angle? What if the angle is 90 degree (the tangent value is infinity)? In addition, how is the angle defined? The angle between curve tangential direction and x-axis? yaxis?

Zhen

[Is is possible to deform a trimesh by following the deformation of a Bspline?]

Hi Heinrich,

I have a further question, is it possible to let the upper curve and lower curve deform differently? For example, let the upper curve deform with B-spline 1, and the lower curve deform with B-spline 2, where B-spline 1 and 2 are controlled by different design variables.

Best,

Zhen

[Is is possible to deform a trimesh by following the deformation of a Bspline?]

This is very cool, thanks for the help!

Zhen

[Is is possible to deform a trimesh by following the deformation of a Bspline?]

Hi Heinrich,

Thanks for the reply, I have attached the project file (currently not working as expected).

Best,

Zhen

test_bspline.fdb

[Is is possible to deform a trimesh by following the deformation of a Bspline?]

Hi,

I am a beginner of CAESES, and I have a problem to design a FFD that can deform the geometry by following the deformation of a B-spline curve. The B-spline is basically the same shape as the curvy part of the geometry, we can deform the B-spline by shifting the control points of the B-spline, so it would be nice that the geometry can deform in the same way as the B-spline curve. I wonder how to make the geometry to follow the same deformation?

I have attached a figure with geometry and the B-spline before and after deformation,  an example of the fdb file would be highly appreciated, thanks for the help!