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!
Solved! Go to Solution.
Solved by sboon. Go to Solution.
Yes, using the ConditionalHorizontalTarget subassembly.
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
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.
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.
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
Can you not use offset alignments with widenings applied to them?
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
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'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.
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
He can just graphically slide the transitioning grips to change the Transition Segment length if he changes the length of the Parent alignment.
You can do this also with the help of the Subassembly Composer and some API calls, no Offset alignments required.
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
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.
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.
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.
Great Advice!
My problem seemed to be fixed by changing the default settings.
Thanks to everyone for their spectacular help.
Cheers
Aaron
@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!
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
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