Breaklines and contours

[pmwolfe]

Hello,

I'm having problems contouring in C3D 2014.

I'm using the command PL - polyline to create my break lines (Centerlines, top and bottom of curb) probably a bad idea?.

In this particular drawing the first point I click on is carrying the elevation throughout the entire length and yielding bad contours.

Essentially the bottom of curb on each side of the street should be the same elevation with a crown at the centerline.

Instead the elevations are about five feet different because the beginning point is around the corne at a point of tangency on a hill.

This has not happened in any other drawings and I've done them the same way.

I redid the breaklines with the 3DPOLY command and aside from a few minor edits the surface came out OK.

I've been reading about 3DPOLY command but have not found out too much about what the actual difference is between 3DPOLY and PL commands.

Seems like 3DPOLY is the way to go. 

I do not have too much experience with C3D 2014 and am making a huge jump from 2004 LDD.

I've basically had to figure out all of what I know by myself and I'm turning to the community for some help and guidance.

Most likely I'm doing a number of things wrong and if someone knows of some good tutorials or websites to learn from or would care to go into detail how to build 3D surfaces/contouring I'm all ears.

Regards,

Mike

[Jay_B]

Polylines assume the Elevation first snapped to and carry that same elevation out the entire length of the line.

If you wish to have each verticie of a Polyline assume the Elevation of each individual snapped point then a 3DPoly must be used as this type of Polyline can have differing Z coordinates at each vertex.

If your drawing lines into a survey you might want to look into Survey Databases and Survey Linework as the linework can be easily automated using this feature on future surveys.

[jmayo-EE]

I also recommend automating the linework creation. Even if you can't get a field crew to change coding or if you have the data from an outside source it is worth the time creating an excel spreadsheet that can translate the code to your needs and export the points back out. If you create breaklines by hand regularly you can save hours of work.

If you must draw the breaklines by hand I would recommend using feature lines over 3d polys. The editing tools are better, you can have real curves in the breaklines and you can transition elevations between know points as you create them.

[pmwolfe]

Thanks for the responses.

So I've recontoured using 3DPOLY and the surface more or less comes out correct except for a few areas where contours are going crazy.


I've gone into:?Settings --> Surface --> Commands --> Create Surface --> Edit command settings --> Build options --> and checked allow crossing break lines & Use first breakline elevation.

Drew my breaklines with 3DPOLY, then created my surface, named it, selected and added my breaklines, then my border and then my point group.

Points where contours go crazy are at or near same elevation and should have contours around them not through them.

Any ideas?

Eventually I will be implementing Field to Finish techniques but for now I need to do it without that luxury.

Thanks,

Mike

[tcorey]

Hi Mike,

You should edit your surface properties and move the boundary to the bottom of the list, after where you add the point group. It makes a difference.

I don't know if this will help your particular issue, I'd have to see the drawing, but this is a "best practice."

Tim

[pmwolfe]

Tim,

Thanks for the tip.

They are arranged with breaklines first, then point group, then boundaries last.

However, it didn't help out in this case.

Contours still pull for reasons beyond my knowledge.

Mike

[troma]

Can you post a picture of the problem area?

[pmwolfe]

It should basically look like a normal road with a crown centerline and gutters along the curbs.
I used 3DPOLY to go around the curves. I did not have a full compliment of shots from the field to accurately draw the top of the curbs at the corners.
I simply left the last node and then clicked in space near and along the top of curb and the reattached to a node on the other side of the curb.

Perhaps actual field data (points) for top of curb an bottom of curb must be used for every segment of the 3DPOLY line?

Mike

[troma]

If you convert your 3D poly to a featureline, you can use the elevation editor to grade from point to point in a straight grade, ensuring that all the points round the bend are at the same grade.