Drawing a hyperbola

Jan:

I am in the process of creating a sag line and I am told that the catenary by points will do it.

The word catenary derives from the Latin for chain, and describes the curve of a chain or rope tethered between two points.

I'm not familiar with catenaries or the MicroStation tool for generating one. On first glance it looks fairly straightforward: you need to specify a 3D start point and end point, and catenary constant k. You need to talk to your line engineers to determine the k-factor.

Regards, Jon Summers
LA Solutions

P.S. Netiquette suggests that it would be better to start a new thread for your new topic.

Hi Jon:

 Maybe you could point me in the right direction.  I am in the process of creating a sag line and I am told that the catenary by points will do it but I can't figure out how to plug the numbers in, like name and expression.  I guess what I am looking for is an example of thow the formula is done.  Any suggestions that you can offer?  I do see that the curve calculator has the formula just trying to figure out what to plug in.

Thank You

Jan

Thanks for the reply. I found the hyperbola and also tried the offset curve. The B-spline works best and it's just like CorelDraw. There's a serious problem with all three methods: I cannot connect the B-spline with an arc using Modify Elements/Extend elements to Intersection in order to make a closed element. of an arc and the B-spline withtheir concave sides toward each other. Putting the cursor on the B-spline gives me a message "Element type not valid for this tool."

 I'm practicing drawing gears. I can do straight spokes, tapered spokes but not spokes formed by hyperbolas on either side. I need to connect a B-spline with an arc. Is this possible?

dbvogt:

I need to draw a hyperbola.

1. The arc tools do not seem to allow any variation from a pure section of a circle
2. CorelDraw can create what I want by creating an arc and pulling the middle out so forming Bezier curves

1. The arc tools do not seem to allow any variation from a pure section of a circle

   A MicroStation arc is a section of an ellipse. A circle is a special case of an ellipse.

2. CorelDraw can create what I want by creating an arc and pulling the middle out so forming Bezier curves

   Those illustration tools! They make geometry seem so easy.

B-Spline curves are Bezier curves on steroids. In fact, a Bezier curve is a simple form of a B-Spline curve. One solution you have is to use the B-Spline Curve tool palette to create a curve. You will find that the handles provided by MicroStation let you manipulate the curve.

An alternative is the Curve Calculator. If you know the algebraic equation of a curve, such as a hyperbola, then the Curve Calculator will draw it for you.

Regards, Jon Summers
LA Solutions

I'm just learning Microstation and the need arose to draw a hyperbola. The arc tools do not seem to allow any variation from a pure section of a circle. Place smartline with a vertex type set to rounded appears to do the job but it requires placing many points and just creates sections of smooth curves, not a smooth curve from one endpoint to the other. Any suggestions?

I've used CorelDraw for some years for simple one-off sketches and it can create what I want by creating an arc and pulling the middle out so forming bezier curves.