29 Replies Latest reply on Aug 11, 2018 11:20 AM by Maha Nadarasa

# Equation Driven Curve

Equation Driven Curve is creating a small gap how to get rid of this gap? 2 is over defining the sketch but 1.999 is creating a gap.

pi*10 should be the correct one but it gives over defined sketch. I reduce the number and tried.

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Maybe make it in two pieces?

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Hi maha,

Do it in 2 steps,

First 1 EquationDrivenCurve between 0 and pi, and after another from pi to 2*pi. After that you can use composite curves to merge both Curves in 1. Cheers

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Thanks

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Hey Maha,

That is an intriguing shape, may I ask what it is?

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Once I complete the work I will attach the file.

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Why does pi*10 not respond? here 10 is diameter.

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Hi Paul,

Fit spline won't result exactly the same curve as original. It's an approximation.

Regards.

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Marcos,.. yes,..it's an approximation set with a tolerance on the curve(or entites) selected.

..question,.. assuming the equation is absolute,.. and,..the curve generated is created within the kernel tolerance/limits of Parasolid.....is the equation generated curve (parasolid) also a approximation?   "yes/no"

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An equation is an equation, pure mathematics, if you draw y=x^2, you will get an exactly math curve, in your screen. So answer is not, not an approximation.

Fit splines are approximations, internally different equations to the one we want.

Cheers.

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Thanks Marcos,..  appreciate that!

So,.. maybe it's more of a question of  "Absolute/Perfect geometry" in the real world of... science or engineering?

..this Absolute Perfect Curve Driven by a Equation...  can only remain perfect,.. by itself, used only within the SolidWorks (a vacuum if you will) or a *.sldprt... that is, if we export that perfect curve,.. it looses the link to the driven equation and  perfection and will become a approximation/tolerance per the kernel (or other modeling kernel which imports it).

..now, in the above sweep example,..  when we introduce a circle normal to the end of this "perfect curve",.. and apply a Sweep Feature (in this case.. or any feature)... will the topology be perfect,..and/or, will it be perfect when we export it to X_T or STEP or IGES?

From my perspective,... using 3D tools or working within a realistic tolerance (approximation),.. you may begin with a absolute perfect curve. .but the subsequent feature processes would degrade the original perfect curve.. so.. if the intent is perfection (science).. is would be quickly lost with Solidworks features alone.. and later within manufacturing tolerance processes.

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Hi Paul,

Don't take it personal. Your solutions works too, but it's not as good as mine ....

My answer should be the Correctest!!!!

Cheers.

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Marcos,.. I don't care about the points (or it being personal),  it's not about right/wrong,  for me, it's about options which create a design within tolerance... and, I appreciate your input,.. you got 1000 points.

Correctness (+/-?) =  what are the tolerance differences between the two curves (Fit Spline and Composite Curve) and finally creating the two child Sweep features or the end result/goal?

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Hi Paul,

Thanks for the badge, my first one.

I've learnt new things from these forums. I think this is the most valuable thing. Maha had a problem and we gave 2 different options. His main issue was to understand the parametric equations when use trigonometry and the values of angles in radians.

Your answers weren't clear and resulted confusing. Nobody talked here about kernel, export, machinning, etc...  Only you.

Actually I've just extended the answer of:

###### that was right.

I wrote 'correctest', meaning the most correct in a funny way. I knew was wrong.

Cheers.

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..for anyone interested,.. and for reference,.. here are two ways to convert the two halve equations using the Composite Curve and Fit Spline and their compared volumes ... Also.. doing a manual layout, no equations for those who would like to use planes/sketches/curves.

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If a gap is tiny it will not make any issue. So far I have no problem with this.

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Hi Maha,