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Transitions Between Assemblies

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Message 1 of 20
aafulton
5527 Views, 19 Replies

Transitions Between Assemblies

Hi All,

 

I have two assemblies that represent road cross section at two points along a corridor. I want the corridor to transition smoothly between the two cross section so that if I look at a section halfway between the two assemblies it will have an intermediate width. Doing this with a simple transition assembly doesn't seem to be the most efficient approach since my offset or target actually changes as one moves up the corridor. Has anyone figured out a way to accomplish something similar? Is there a way to generate a polyline or some other type of entity that could be used as a target?

 

Cheers!

19 REPLIES 19
Message 2 of 20
fcernst
in reply to: aafulton

Yes, using the ConditionalHorizontalTarget subassembly.



Fred Ernst, PE
C3D 2024
Ernst Engineering
www.ernstengineering.com
Message 3 of 20
aafulton
in reply to: fcernst

Hi Fred,

 

Could you please elaborate on how that subassembly actually works given my scenario. I've used it before when I want my corridor to search for various targets but ca't figure out how I can get the transitioning width behaviour. Seems like my problem could be solved if I could just figure out a way to create a polyline whose offset distance varies along its length.

 

Thanks for your time,

Aaron

Message 4 of 20
fcernst
in reply to: aafulton

I was just answering your last question there..

 

Sounds like a normal horizontal transitioning scenario. What's going on?

 

Throw us a bone...provide a picture.

 



Fred Ernst, PE
C3D 2024
Ernst Engineering
www.ernstengineering.com
Message 5 of 20
sboon
in reply to: aafulton

Hello Aaron,

 

First off - welcome to the board.

 

I'm not entirely sure that I understand what you're trying to do here.  Are you familiar with offset alignments?  Based on your description it sounds like that would be the solution for you.

Steve
Expert Elite Alumnus
Message 6 of 20
aafulton
in reply to: sboon

Thanks for the welcoming spirit. Yeah I am totally familiar with offset alignments and using alignments, featurelines, and profiles for targets in corridors. I found a work around that is decent but not as elegant as I had hoped for. The attached image shows the results of my efforts. I created a tapered polyline offset and used those offsets as target alignments to vary the width of a channel along a corridor. I was hoping to have something that is more dynamic....i.e. if I were to change my alignment geometry the variable width (target offsets) would adjust automatically rather than having to manually create the tapered polylines each time my aligment changes.

 

Let me know if there is a more elegant way of doing this.

 

Cheers,

Aaron

Message 7 of 20
Neilw_05
in reply to: aafulton

Can you not use offset alignments with widenings applied to them?

Neil Wilson (a.k.a. neilw)
AEC Collection/C3D 2024, LDT 2004, Power Civil v8i SS1
WIN 10 64 PRO

http://www.sec-landmgt.com
Message 8 of 20
aafulton
in reply to: Neilw_05

Thanks for the great help folks,

 

I'm a little confused on how I would specify a varying width offset. The create widening specifies a lateral widening that would work for a bus stop or widening that then would transition back to the regular offset. My previously posted image sort of show what I'm trying to do via the brute force method. I gues the real question is, can I create an offset alignment whose offset varies as a function of the station value. For instance, if I want a 20 foot offset at station 0+00 and a smooth transition to an offset of 10 feet at station 10+00. The offset alignment wouldn't be a true parallel offset but would neck down or taper as a function of station value.

 

Cheers,

Aaron

Message 9 of 20
sboon
in reply to: aafulton

Here's a drawing with two offset alignments.  I've adjusted the stationing of the widenings so that essentially the entire length of the offset alignment is a taper.  You can edit the centerline and the offsets will adjust so suit.

Steve
Expert Elite Alumnus
Message 10 of 20
Neilw_05
in reply to: aafulton

Steve's drawing should give you the idea. You may have to finagle the start and end regions a bit to get the taper to be fully within the range of your centerline.

Neil Wilson (a.k.a. neilw)
AEC Collection/C3D 2024, LDT 2004, Power Civil v8i SS1
WIN 10 64 PRO

http://www.sec-landmgt.com
Message 11 of 20
aafulton
in reply to: Neilw_05

This is exactly what I was trying to do. I didn't realize you could manage the offsets and tapers in the offset alignment properties!

 

Consider this one solved!

 

Cheers to all,

Aaron

Message 12 of 20
fcernst
in reply to: Neilw_05

He can just graphically slide the transitioning grips to change the Transition Segment length if he changes the length of the Parent alignment.



Fred Ernst, PE
C3D 2024
Ernst Engineering
www.ernstengineering.com
Message 13 of 20
fcernst
in reply to: aafulton

You can do this also with the help of the Subassembly Composer and some API calls, no Offset alignments required.

 

 

 

 

Capture.JPG



Fred Ernst, PE
C3D 2024
Ernst Engineering
www.ernstengineering.com
Message 14 of 20
aafulton
in reply to: sboon

Hi Steve,

 

Your alignment drawing worked perfect. Could you explain how you actually went through the steps of creating the offset alignment and then tweaking the widening. Did you use some type of constraint or do it manually?

 

Cheers,

Aaron

Message 15 of 20
sboon
in reply to: aafulton

Start by creating a very basic centerline, just a straight line from your proposed start point to end point to get started.  Before you create any offset alignments you likely need to edit the default settings for the Add Widening command.  Otherwise your transition segments through curves don't work very well.  The default settings can also cause the command to fail, because the segment and transition lengths won't fit within the overall length of your alignment.  Here's what I'm using for the example drawing.

 

Clipboard01.png

 

Use the Create Offset Alignments command from the Ribbon then select one of the new alignments and use the little cyan + icon to create the default widening.  Once that's done you can select the alignment again and pick on the white dot in the middle of the transition.  This should turn on two new cyan grip points which allow you to drag the start and end of the transition.

 

Clipboard02.png

 

You cannot move them to the absolute ends of the centerline alignment (if you do then the transition disappears and you have to recreate it) but you can use the station-offset transparent command to get them close enough.  The idea is to have that one transition cover the entire length of the centerline.

 

Once you have all of that done you can go ahead and start editing the centerline to add PI's and curves etc.  Note - you can also try to do this step first, but I've sometimes had difficulty creating the widenings if the centerline already has complex geometry.

 

Steve
Expert Elite Alumnus
Message 16 of 20
aafulton
in reply to: aafulton

Great Advice!


My problem seemed to be fixed by changing the default settings.

 

Thanks to everyone for their spectacular help.

 

Cheers

Aaron

Message 17 of 20
BrianHailey
in reply to: sboon


@sboon wrote:

 Before you create any offset alignments you likely need to edit the default settings for the Add Widening command.  Otherwise your transition segments through curves don't work very well.

 


I KNEW there had to be some way of changing that! Thanks Steve!

Brian J. Hailey, P.E.



GEI Consultants
My Civil 3D Blog

Message 18 of 20
sreenubachu
in reply to: sboon

can explain sep by step procedure for assembly for varying width
Message 19 of 20
sboon
in reply to: sreenubachu

The steps in the previous comments explain how to create an offset alignment.  The next step is to use that as a target for your corridor.  Make sure that you use an appropriate lane subassembly in your assembly; the BasicLane one doesn't have the option for widening so you cannot use it for this.

 

Once you have a corridor, you can edit the Target Parameters so that the offset alignment controls the width of the lane.

 

Steve
Please use the Accept as Solution or Kudo buttons when appropriate

Steve
Expert Elite Alumnus
Message 20 of 20
hogan.calvin
in reply to: fcernst

Could you explain this concept in further detail?

Thank you.


Cal

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