Equation of a line
Equation of a line
(OP)
Hi all,
I hope someone can help me, I've tried searching this forum but no luck. I need to create an acrylic lens with the shape determined by the following equation: Y=50 -2.75(sqrtX), x=0-250, in mm.
I'm using SW 2006, SP0. I use equations for setting dimensions, but can't seem to figure this out. I know I could create a table with discrete X and Y values, but this would not really be what I want.. might be the best I get though :)
Thanks for any help,
Bob
I hope someone can help me, I've tried searching this forum but no luck. I need to create an acrylic lens with the shape determined by the following equation: Y=50 -2.75(sqrtX), x=0-250, in mm.
I'm using SW 2006, SP0. I use equations for setting dimensions, but can't seem to figure this out. I know I could create a table with discrete X and Y values, but this would not really be what I want.. might be the best I get though :)
Thanks for any help,
Bob
"You can observe a lot just by watching"
Yogi Berra






RE: Equation of a line
Your function is a paraboa. So, you can use Paraboa sketch entity. It can be found at \Tools\Sketch Entities\Parabola\...
Good Luck!
Alex
RE: Equation of a line
Calculate position of 4 points and constrain a sketched parabola to them.
RE: Equation of a line
Just currious (nosey I suppose). Why would fixed points and a spline be unacceptable? Are you cutting a lens tool direct from the model or perhaps exporting the data for lighting analysis? OptisWorks Ray Trace Add-In uses fixed points and a spline for generating optical surfaces so if you have enough points the calculations should be fine. I got tired of not being able to edit the surface when my OE changed the design so created a table driven curve with several points (50ish) where I could enter the ZEMAX data and update the surface. Most OE's and lens suppliers specify the surfaces using the radius, conic and diameter so I'm not sure how much this will help given the post. If lens creation (especially aspheres) is something you do on a regular basis then perhaps this will be of some use.
For SW09 you can use the formula driven curve feature so no need for a table or the fixed points/spline. The results that I had with the table driven parts in SW08 and the parts I've made in SW09 give me the same results in OptisWorks Ray Trace.
The formula is y=(x^2/R)/(1+(1-(1+b)/(x/R)^2)^.5)
where x = the start and end points ( 0 and the lens diameter /2)
R = the lens prescription radius
b = the conic constant (Rho)
For a sphere the conic = 0; for an Ellipse 0>b>-1; for a Parabola b = -1; and for a Hyperbola b< -1
I am aware that most users won't need or want conics, but for optics and opto-mechanical designers it is handy.
Harold
SW2009 SP2.0 OPW2009 SP0 Win XP Pro 2002 SP3
Dell 690, Xeon 5160 @3.00GHz, 3.25GB RAM
nVidia Quadro FX4600
www.lumenflow.com
RE: Equation of a line
I've gone ahead and created the part using a table of discrete X and Y values. You're right lumenharold about the fixed points working. Talking with my machinist, by making the points close enough to each other and taking into account the tool radius, my STEP file into the CNC lathe will work just fine.
SW 2006 (this company is Pro-E, but they have one seat of SW for me while I get up to speed, hence the old version) doesn't seem to let me input an equation.
Thanks again, I love this site,
Bob
"You can observe a lot just by watching"
Yogi Berra
RE: Equation of a line
RE: Equation of a line
"You can observe a lot just by watching"
Yogi Berra
RE: Equation of a line
-handleman, CSWP (The new, easy test)
RE: Equation of a line
Harold
SW2009 SP2.0 OPW2009 SP0 Win XP Pro 2002 SP3
Dell 690, Xeon 5160 @3.00GHz, 3.25GB RAM
nVidia Quadro FX4600
www.lumenflow.com
RE: Equation of a line
RE: Equation of a line
Harold
SW2009 SP2.0 OPW2009 SP0 Win XP Pro 2002 SP3
Dell 690, Xeon 5160 @3.00GHz, 3.25GB RAM
nVidia Quadro FX4600
www.lumenflow.com
RE: Equation of a line
Using the focus and apex, one can graphically solve for a parabolic lens shape with much more flexibility than by simply crunching numbers.
RE: Equation of a line
Harold
SW2009 SP2.0 OPW2009 SP0 Win XP Pro 2002 SP3
Dell 690, Xeon 5160 @3.00GHz, 3.25GB RAM
nVidia Quadro FX4600
www.lumenflow.com