Make a Loop

[onsionsi1]

Hi There,

I'm trying to draw a loop between two line but i can't get solution to draw this loop

And this is the criteria of this loop Spiral-Curve-Spiral 

LT1=17.777

R=90

LT2=25.050

Eventually you can find this DWG in the attached file.

Thank you.

[ccoles]

Super easy. I just did that curve in less than a minute using 'Alignments'.

Draw the two tangents through the PI.

Select 'Add Free Spiral-Curve-Spiral' from the alignments menu.

Pick the tangents from down station to up station, and follow the rest of the prompts. Done!

P.S., I opened your file, but don't have the object enabler to see your alignment. If the command doesn't work, the curve will not fit in the space provided. Try reducing the spiral length in and out to see what will fit, and adjust in increments until it gets as close as it can.

[onsionsi1]

Thank you for your reply but if you can make it in my drawing so, i will be appreciate

[ccoles]

What program are you using? It is obviously not Civil 3D. All I see are proxy objects represented by rectangular boundaries.

[onsionsi1]

I'm using Civil 3D 2012 version

[ccoles]

No wonder. I'm using 2011. But the process is the same. If the command doesn't work for you, the tangent segments are too short to fit the curve. Stretch the segments longer or reduce the curve lengths.