AutoCAD Civil 3D General Discussion

Reply
Valued Contributor
bigwill73
Posts: 76
Registered: ‎12-04-2003
Message 1 of 6 (87 Views)

Creating Alignments from existing polyline and AU

87 Views, 5 Replies
12-08-2004 05:51 PM
Well it was my understanding while at AU that when creating alignments from a polyline you do not have the same tangency control (if gripped by the curve) that you have when you create an alignment using tan-tan w/ curve. Is there a way using tan tan w/curve to essentially trace over the polyline but giving it that same grip response and curve tangency association that is lost when created from polyline only. I've been fooling around w/ it for a couple of days now and can't seem to get it to work.

On another note AU was a blast. My first year there and it exceeded my expectations and It lived up to the booster shot image. I saw quite a few familiar names from the LDT and C3D boards that I was actually able to place faces to. And some actually spoke or assisted at some of the Civil 3D courses I attended. Great job guys. What a wonderful event. I'll be there next year.

BigWill
*Chakri Gavini
Message 2 of 6 (87 Views)

Re: Creating Alignments from existing polyline and AU

12-09-2004 04:41 AM in reply to: bigwill73
Morning BigWill, If your polyline is of just line segments (without any arcs) in its definition - then you can convert that polyline into an alignment with "add curves between tangents" option selected. Such an alignment would maintain tangency rules and if you want to change later radius of any curve can be done easily through the alignment editors. However if you already have some plan geometry with arcs in it and want to convert as an alignment - that too can be accomplished using various tools on layout tool bar. Suppose you have Tangent-Curve-Tangent-Curve-Tangent as your polyline. For such cases i would use the following approach: 1. In the layout toolbar pick "Fixed Line (Two points)" option from lines commands; End snap to the first line segment in pline 2. For the arc following - use "Floating Curve (attach to entity end, through point)" and select previous line and osnap at the other end of the arc that you want to trace. 3. For the second tangent - use "Floating Line (always tangent to end of entity)" option; select the previous curve and for length of the line osnap end of curve to end second tangent in the pline. 4. Repeat #2 and #3 for second arc and third tangent. I used this procedure many times so far and worked fine. depending on your requirements and geometry you may have to followdifferent approaches - including entering dummy entities first and then editing data in the grid editor as a tabular entry! Hope this helps Chakri "bigwill73" wrote in message news:26172416.1102557104153.JavaMail.jive@jiveforum1.autodesk.com... > Well it was my understanding while at AU that when creating alignments from a polyline you do not have the same tangency control (if gripped by the curve) that you have when you create an alignment using tan-tan w/ curve. Is there a way using tan tan w/curve to essentially trace over the polyline but giving it that same grip response and curve tangency association that is lost when created from polyline only. I've been fooling around w/ it for a couple of days now and can't seem to get it to work. > > On another note AU was a blast. My first year there and it exceeded my expectations and It lived up to the booster shot image. I saw quite a few familiar names from the LDT and C3D boards that I was actually able to place faces to. And some actually spoke or assisted at some of the Civil 3D courses I attended. Great job guys. What a wonderful event. I'll be there next year. > > BigWill
Valued Contributor
bigwill73
Posts: 76
Registered: ‎12-04-2003
Message 3 of 6 (87 Views)

Re: Creating Alignments from existing polyline and AU

12-15-2004 07:50 AM in reply to: bigwill73
Chakri,
Thanks for the tip. I'll give it a try.

BigWill
Valued Contributor
bigwill73
Posts: 76
Registered: ‎12-04-2003
Message 4 of 6 (87 Views)

Re: Creating Alignments from existing polyline and AU

12-29-2004 06:11 PM in reply to: bigwill73
Chakri,
How would you handle the same example but with a compound or even reverse curve.in between somewhere in an alignment so the curves maintain tangency as well.

Thanks,
BigWill
*wfb
Message 5 of 6 (87 Views)

Re: Creating Alignments from existing polyline and AU

12-30-2004 05:40 AM in reply to: bigwill73
Obviously, my name is not Chakri, but I am giving you my method. Since this takes hardly any more time. 1. Explode the existing polyline. 2. Fillet "0" the tangents together for P.I.'s 3. Run the Alignment by Layout without any radii. 4. Insert Curves by using radius. This maintains the P.I.'s and holds tangency, which some of the other methods do not seem to. Bill "bigwill73" wrote in message news:7022933.1104372725414.JavaMail.jive@jiveforum1.autodesk.com... > Chakri, > How would you handle the same example but with a compound or even reverse curve.in between somewhere in an alignment so the curves maintain tangency as well. > > Thanks, > BigWill
Valued Contributor
bigwill73
Posts: 76
Registered: ‎12-04-2003
Message 6 of 6 (87 Views)

Re: Creating Alignments from existing polyline and AU

01-06-2005 05:44 AM in reply to: bigwill73
Bill,
thanks for the tip. Actually I have been doing something very similar to this already but without 0 fileting my plines. I just snap app int. and manually enter the curve radius at each varying curve. I need help on reverse curve and compund curve situations now.

Thanks again,
BigWill

You are not logged in.

Log into access your profile, ask and answer questions, share ideas and more. Haven't signed up yet? Register

Announcements
Are you familiar with the Autodesk Expert Elites? The Expert Elite program is made up of customers that help other customers by sharing knowledge and exemplifying an engaging style of collaboration. To learn more, please visit our Expert Elite website.

Need installation help?

Start with some of our most frequented solutions to get help installing your software.

Ask the Community


Civil 3D Exchange Apps

Created by the community for the community, Autodesk Exchange Apps for AutoCAD Civil 3D helps you achieve greater speed, accuracy, and automation from concept to manufacturing.

Connect with Civil 3D

Twitter

Facebook

Blogs