How can I start alignment and profile from a minus number?

[Bin2009]

Hello,

I am doing crossing drawing, I created alignment and profile use CIVIL 3D, but I need set 0+000 on the center of my alignment and profile, where is the corossing ceterline location, so my alignment and profile have to be start with a minus number. But, always, when I creat alignment, it start with 0+000, if I set up start number to for example, -0-750, my profile will only start from 0+000, the first 750m profile will dispear.

Please help me if you know how to show profile in minus side.

Thanks

[Jay_B]

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Bin2009 wrote:

 But, always, when I creat alignment, it start with 0+000, if I set up start number to for example, -0-750, my profile will only start from 0+000, the first 750m profile will dispear.

Please help me if you know how to show profile in minus side.

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It works fine in the attached tutorial drawing. I set the -7+50 in "Alignment Properties" as shown by entering -750 in the Reference Point>Station: box.

[MikeEvansUK]

I generally drag the alignment to start at zero then add a line from where the negative value to zero is. This helps with labels, also superelevation & snapping in profile views as it will draw a horizontal geometry grid line.

[Bin2009]

Hello, Jay,

Thank vert much for your reply,

I used same way as you set up reference point to  -750,(see attachment: set_up _start_point_to_0.png)

before the drawing is looks like attachment: Alignment_start_with_0.pdf

after I change, the drawing like attachement: Alignment_start_with_minus750.pdf

It still missing the profile form -750 to 0.00.

Please look my drawing and help me figue out.

I only have Civil3D 2012, can not open your DWG file, could you please save as lower revision, I will be able to look your drawing.

[Jay_B]

Here's a 2012 dwg.

Post your drawing here so someone can take a look.

[ccoles]

It appears as though the profile for the surface is not dynamic, but static in the profile view. You may need to build the surface profile again, making sure it is added as dynamic so any additional changes to the profile stationing will update automatically.

[Bin2009]

I didn't creat surface, I use a 3D polyline creat alignment and profile, because I only have the N. E, and elevation of the points along my pipeline, don't have survey data.

Here is my drawing, 

Thanks

Bin 

[Bin2009]

Yes, I looked your drawing, it looks work well, maybe I need build surface first.

Thanks.

Bin

[Jay_B]

Recreate the profile from the 3D entity used, without a surface it's not going to dynamically update

when the alignment is changed. The 3d entity used for profile didn't appear to be in the drawing.

I was able to get the entire profile length to appear but have no way of verifying if the profile is at the

correct elevations and stationing. The profile view drirection was flipped from right to left to match

your stationing.

I've attached the drawing but again it may not even be close to correct.

[Joe-Bouza]

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@mikeevans wrote:
I generally drag the alignment to start at zero then add a line from where the negative value to zero is. This helps with labels, also superelevation & snapping in profile views as it will draw a horizontal geometry grid line.

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Hi Mike

I cant vizualize what you describe, but it sounds interesting. got a picture to help?

[ccoles]

I agree with Jay_B. You will need to re-project the 3d polyline to the profile if you make any changes to the alignment, especially the stationing. Projecting objects to the profile is not dynamic, and will not change to match the alignment edits.

[Bin2009]

Hello Jay,

I checked the profile you created is correct, could please let me know how to "Recreate the profile from the 3D entity used", Thank a lot.

Bin

[Jay_B]

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@Bin2009 wrote:

I didn't creat surface, I use a 3D polyline creat alignment and profile, because I only have the N. E, and elevation of the points along my pipeline, don't have survey data.

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I was referring to the original 3D polyline you mention.

Get the alignment stationing as desired and recreate the profile using your previous steps and 3d polyline.

The problem is when the alignment stationing is changed after you've created the profile using this method

the profile isn't dynamic.

[Bin2009]

Hello Jay,

Thank for your reply, and sorry for that I reply so late.

Now my friend told me a way to creat profile with minus start point, after I change start point refrence point, use commond `projet object to profile`, then I click the new Alignment, I will get the profile start with minus number.

The reason I didn`t use the way as you said ``recreate the profile using your previous steps and 3d polyline`` . because the way I use for creat profile from 3d polyline is quite complex. what I use is:

1. use the excel file with N. E. Elevation to creat 3d polyline,(the excel file with N. E. Elevation is only thing I have)

2. use ``quick profile`` to get a temparary profile

3, export Landxml file from the profile

4 import this landxml file to civil 3d, get an alignment, then use the alignment to creat a rofile.

so if I use the same way to creat profile, always I got profile start with 0+000,

I don`t know what way you use to creat profile from a 3d polyline.

Thank very much,

Bin

[Jay_B]

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@Bin2009 wrote:
The reason I didn`t use the way as you said ``recreate the profile using your previous steps and 3d polyline`` . because the way I use for creat profile from 3d polyline is quite complex. what I use is:

1. use the excel file with N. E. Elevation to creat 3d polyline,(the excel file with N. E. Elevation is only thing I have)

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Bin,

I don't normally create profiles from 3d polylines as in our workflow we almost always create an Existing Surface.

In that case I would import the 3d polyline landxml >Convert that 3d polyline to a Feature Line using "Create Feature Line from objects", offset the Feature Line 10 meters or so left and right.

Then Create an EG surface from these 3 feature lines and along the centerline of your alignment the elevations will be correct, sample an existing ground profile using this surface. 

This will allow for the alignment start station to be adjusted as desired.