tangents and lengths

[Richard McDonald]

More of a how to draw question that CAD Support.

I have 5 radii with known lengths, I know the orientation of the first arc and all the other arc are tangential.

Is there any way to calculate the orientation of the other arc?

[Mike.Perry]

Hi

If I am understanding ( unlikely ), take a look at the following thread...

Draw Arc's that are continuous and tangential

Have a good one, Mike

[Richard McDonald]

Many thanks Mike but those suggestions would either give an approximate length or approx. radii.

I have a feeling this is an impossible task and require either a centre of end coordinate.

[Mike.Perry]

Hi

No worries...

Is it possible to post what you have ( and what you need to achieve, end result ).

Have a good one, Mike

[Richard McDonald]

Here's roughly what I've been given.

[.T.]

The way I check to see if an arc is tangent with another arc quickly is to draw a line from the common endpoint of the arcs to the center of one of the arcs. If the distance from the center of the other arc perpendicular to the line is 0.00, I'm golden. (see attached) This also works for reverse curves.

I don't know if it will help you or not, but maybe it will give you some ideas.

[Maverick91]

Here's roughly what I've been given.

looks like a spiral in a road alignment to me.

[.T.]

looks like a spiral in a road alignment to me.

Ooooo, looking at it again, with the differing radii at each end, you are probably right. That's out of my league. Are there any railroad guys around here?

<Schultz's voice on>I know not'ing, not'ing, not'ing.<Schultz's voice off>

[andy.manninen]

More of a how to draw question that CAD Support.

I have 5 radii with known lengths, I know the orientation of the first arc and all the other arc are tangential.

Is there any way to calculate the orientation of the other arc?

The way i would do this is with your first arc drawn, draw your second arc as a polyline, so you have more options, set the appropriate radius and then use the LENGTHEN command to get the arc to the correct length, rotate the second arc to be tangental (the way Tim Creary explained), draw your next arc and lengthen and rotate, ETC ETC..
does that help? pretty painful and slow, but workable...
:Cheers:

[Maverick91]

Ooooo, looking at it again, with the differing radii at each end, you are probably right. That's out of my league. Are there any railroad guys around here?

<Schultz's voice on>I know not'ing, not'ing, not'ing.<Schultz's voice off>

I deal with spirals on occasion for alignments for APM systems. When LDT creates a spiral, it's actually made up of ten curves of differing radii, from a real big number down to the something close to the radius of the next circular curve. However, I don't know a way of quickly and easily doing what he wants to do here