
Re: conic sketch help
John Stoltzfus Jan 12, 2018 3:26 PM (in response to Jennifer Stark)A conic sketch is multiple radius  like a French Curve....

Re: conic sketch help
Jennifer Stark Jan 12, 2018 3:28 PM (in response to John Stoltzfus)I know, but was hoping there would be some kind of equation to calculate a close radius

Re: conic sketch help
John Stoltzfus Jan 12, 2018 3:31 PM (in response to Jennifer Stark)You could add a few points and use a 3 point circle and make the circle a construction line, then snap dimension on that circle, then as you change the conic sketch, the circle will move with it..



Re: conic sketch help
J. Mather Jan 12, 2018 3:47 PM (in response to Jennifer Stark)Attach your *.sldprt attempt here.

Re: conic sketch help
Jennifer Stark Jan 12, 2018 3:54 PM (in response to J. Mather)Working on a confidential project,I wish I could to make it easier to get help.

Re: conic sketch help
J. Mather Jan 12, 2018 3:57 PM (in response to Jennifer Stark)Seems like this requirement would be relatively easy to reproduce in a dummy part that exhibits the behavior needed in the proprietary design.

Re: conic sketch help
Jennifer Stark Jan 12, 2018 4:27 PM (in response to J. Mather)It might be, but I am at a loss

Re: conic sketch help
J. Mather Jan 12, 2018 4:30 PM (in response to Jennifer Stark)A conic section is exactly that  a planar section through a cone.
The type of section (circle, ellipse, parabola...) is dependent on the size of the cone and the position and angle of the plane.
Are you attempting to reverseengineer an existing curve, or are you attempting to create a new curve?





Re: conic sketch help
Christian Chu Jan 12, 2018 3:58 PM (in response to Jennifer Stark)conic curve can be elliptical, parabolic or hyperbolic  how it can be defined for your measurement?




Re: conic sketch help
Jennifer Stark Jan 12, 2018 4:30 PM (in response to Dan Pihlaja)is there any way to get a list of the radius through the curvature?


Re: conic sketch help
Rob Edwards Jan 12, 2018 4:42 PM (in response to Jennifer Stark)Hi Jennifer
I think it's possible to sub divide any conic into two smaller conics
like this
repeating again
Once you have enough its easy enough to approximate with 3 pt arcs
Solidworks isn't bad at keeping up with changes, but its best to not do BIG jumps, or the sketch solver gets lost
and you have to suppress or delete a relation or two so it solves again
2016 attached

conic subdivision.SLDPRT.zip 50.2 KB

Re: conic sketch help
Jennifer Stark Jan 12, 2018 4:50 PM (in response to Rob Edwards)Trying to backwards engineer this part, need to get radius for boss. I will look at how you have your pictures thank you Rob




Re: conic sketch help
Jennifer Stark Jan 12, 2018 5:56 PM (in response to Rob Edwards)I will try both options. I am not very familiar with using this command. Completely new to me, but hopefully with all your help I can figure this out.




Re: conic sketch help
Roland Schwarz Jan 12, 2018 7:38 PM (in response to Jennifer Stark)A conic has multiple radii!
..wait... did someone already mansplain that???

Re: conic sketch help
Roland Schwarz Jan 12, 2018 7:41 PM (in response to Jennifer Stark)Maybe...
If you're trying to measure instantaneous radius at a point, you could possibly attach an arc and use equal curvature constraint.
It may not work within the same sketch originating the conic. You might have to do this in a second sketch.

Re: conic sketch help
Jennifer Stark Jan 12, 2018 8:30 PM (in response to Roland Schwarz)Yeah I know it’s multiple radii, they want to know out of all the radii the smallest one.


Re: conic sketch help
Rob Edwards Jan 14, 2018 3:02 PM (in response to Jennifer Stark)Hi Jennifer, Completely unrelated I just stumbled upon this in the API and thought it might help you.
2016 SOLIDWORKS API Help  Find Minimum Radius of Curve (VBA)
Looking at the code it requires a model edge, so to test it I just made a planar surface with a conic edge.
I then used the output to draw a circle. Note the coordinates returned are the point on the curve, not the center of the circle so I tested it like this....
looks good to me



Re: conic sketch help
Harold Brunt Jan 15, 2018 1:15 PM (in response to Jennifer Stark)The conic sketch tool in SW uses a different form than typically found in optics which is what I have used with the Formula Driven Sketch Tool. I use the formula driven sketch with this form:
y = (x^{2}/R) / (1 +√[1  (1+K) ∙ (x/R)^{2}]),
Where: The axis lies along the yaxis and represents the height as a function of x.
The vertex is at y = 0.
K = Conic constant Rho
R = Radius of curvature.
You should be able to match your existing curve starting with a Conic constant K = 1 for a parabolic.

Re: conic sketch help
Jennifer Stark Jan 15, 2018 1:49 PM (in response to Harold Brunt)Ok I thought this was for the sketch. I just figures out that it's for the conic fillet. Is there a equation to find that information?

Re: conic sketch help
Harold Brunt Jan 15, 2018 2:29 PM (in response to Jennifer Stark)I'm not exactly sure what you're looking for and since you can't share the proprietary design that makes communication just a little bit harder (my company does consulting so I understand not being able to share a design issue!). If you are looking for the radius of curvature for a conic filet then I'm not sure how you will go about getting it. My understanding of the conic sketch tool interface is limited since it does not serve any purpose for me. The formula driven sketch tool allows the formula I posted is (x^{2}/R) / (1 +√[1  (1+K) ∙ (x/R)^{2}]) and can be entered as:
((X^2)/R)/(1+((1(1+(1))*((X/R)^2))1/2)
You need to enter a value for R and values for X1 and X2 to create the curve.
The formula I posted is commonly used in optics and simulation software like Zemax or SPEOS. I know you can't post the part or design but fitting a parabola is proprietary so if you feel you create a new parabola sketch similar to the problem you are trying to solve then perhaps you'll get a solution sooner.
Edit  If you already know this a parabolic you can select the construction points for the sketch and multiply by 2.

